Inducted into the National Film Registry: 1993
As I sit here writing this essay, it is the year 2018, in the city of Los Angeles, California. It’s a sunny, slightly chilly morning. When I look out my window, I see the stubby trees, freshly-watered green lawns, and the stately bungalows of Larchmont— a sleepy residential neighborhood just south of Hollywood. With a few notable exceptions, the surrounding area probably looks just as it did several decades ago, or as it did in 1982— when an ambitious science fiction film named BLADE RUNNER dared to imagine a very different future for Los Angeles. One of the most influential films of all time, BLADE RUNNER is famously set in the year 2019. Imposing monolithic structures dominate a dark landscape awash in surging neon, soaking acid rain, and flying cars. The tree-lined streets and Craftsman dwellings of my neighborhood have long since been paved over and forgotten about, falling into decay if the structures still even stand at all. We are now just one year removed from the dystopian cyber-punk future that BLADE RUNNER envisioned, and it has thankfully failed to materialize. However, one needs only drive through the packed streets of Koreatown at night, or look to downtown’s rapidly growing skyline to see that our steady march to a BLADE RUNNER-styled future is all but inevitable.
In some ways, my personal journey with director Ridley’s Scott’s iconic masterpiece mirrors its long, hard-fought journey to attain its said-masterpiece status amongst the cinematic community. In other words, each successive viewing of BLADE RUNNER functioned almost like an archeological dig— with every new pass, another layer of obscuring dirt and grit was stripped away to increasingly reveal the treasure underneath. My very first experience with the film was on a well-worn videocassette borrowed from my high school library, and it was underwhelming, to say the least. I didn’t really know what I was watching, because the tape was so degraded that the picture was a muddy smear of various browns and blacks. It was enough to put me off the film for several years. I was only able to first see BLADE RUNNER so clearly in 2007, when it received a lavish DVD release complete with a new cut of the film dubbed “The Final Cut”. In the years since, I’ve revisited BLADE RUNNER several times as each successive home video format brings an added clarity and resolution, with the recent 4K UHD release being nothing short of a full-blown revelation. In the lead-up to the writing of this essay, I devoured everything there is to see on BLADE RUNNER— each of the five official cuts, the sprawling making-of-documentary, Scott’s audio commentary, and the exhaustive supply of bonus content made available on the official multi-disc home video release. Despite all this however, much of BLADE RUNNER manages to remain elusive— there is always something new to see, some little story bit or profound insight that decides to finally make itself known. This is a large part of BLADE RUNNER’s enduring appeal: for all the mysteries we like to file away as “solved”, there’s untold more just waiting to discovered.
As the 1970’s gave way to the 80’s, Scott was riding high on on the success of his breakout second feature, ALIEN (1979). His inspired blend of sci-fi and horror proved to be an instant classic with audiences, and catapulted him to the forefront of the American studio system. He quickly attached himself to DUNE, another sci-fi property that styled itself as “STAR WARS for adults”. It was around this time, when Scott was finishing up his sound mix for ALIEN, that a producer named Michael Deeley approached him with the script for BLADE RUNNER, written by Hampton Fancher. Adapted from the 1968 novel “Do Androids Dream Of Electric Sheep?”, by venerated science fiction author Philip K. Dick, BLADE RUNNER told the story of an ex-cop in the futuristic cityscape of 2019 Los Angeles, tasked with hunting and exterminating illegal, artificially-created humanoids named replicants. Even Scott had to admit the project sounded interesting, but with DUNE already on his plate, he declined Deeley’s offer. Sometime thereafter, in 1980, Scott’s older brother, Frank, passed away from skin cancer. The loss of his brother sent Scott into a deep, depressed state that compelled him to drop out of directing DUNE— but it also had the curious side effect of opening him up again to the notion of making BLADE RUNNER. Fancher‘s moody, somber tone must’ve seemed an appropriate match for Scott’s mental state, and upon agreeing to make the film, Scott subsequently enlisted the services of David Peoples to deepen the hard-edged noir grooves of Fancher’s screenplay. In this light, Scott’s approach to BLADE RUNNER serves as something of a grieving process for his late brother— an intensely personal work that reflects some of the director’s most intimate thoughts & memories; a technical triumph and cultural touchstone that transcends its pulpy genre trappings to become a heartfelt meditation on creation, death & loss— the beauty of life as defined by its ephemerality.
The world of BLADE RUNNER, despite the appeal of its flying cars and fizzy blooms of neon, is a future that humankind very much would like to avoid— in this version of 2019, the world is a polluted wasteland of super dense, cramped urban infrastructure bathed in a perpetual shower of acid rain. Animals have long since gone extinct, replaced by replicant versions affordable only to the super rich. Like so much dystopian futuristic fiction, Los Angeles has become an omnipresent police state, and many have left Earth entirely to live in the off-world colonies— much like Europeans sailing towards The New World to begin again in what they believe is an untouched paradise. Bioengineered humans called replicants, or “skinjobs” by those less inclined towards politeness, exist only as a disposable slave workforce— cursed with an extremely limited lifespan of four years. After a violent slave uprising, replicants have been deemed illegal, and specialized bounty hunters called Blade Runners have been commissioned to track them down for early “retirement”. Amidst this brutal cityscape, the camera finds Rick Deckard: a burned-out ex-cop ripped straight out of the hard boiled-noir tradition (right down to the trench coat). Harrison Ford’s portrayal of Deckard may not have reached the same kind of cultural penetration that Han Solo or Indiana Jones did, but his performance here is iconic nonetheless. It’s hard to imagine anyone else in the role— even those who the creative team initially considered, like Robert Mitchum (whom Fancher envisioned during his writing) or Dustin Hoffman (who got far enough in casting talks that the storyboards bear his face(1)). Deckard’s long, hard-fought career has made him weary, cynical… even a bit damaged. On top of all this, he’s dogged by a lingering suspicion that he might just be one and the same with the “skinjobs” he’s hired to exterminate.
Like so many retired ex-cops in this genre, Deckard is inevitably pulled back into service by his old boss at the LAPD, tasked with tracking down a dangerous replicant posse headed by Rutger Hauer’s Roy Batty— a combat-model creation looking to break the lock on his expiration date so he can live forever. Hauer proves an inspired casting choice, with his Aryan looks subtly evoking the eugenic pursuits of the Third Reich, and his channeling of a certain kind of restrained nuttiness (for lack of a better word) resulting in an aura of dangerous unpredictability. His barbed liveliness stands in stark contrast to Deckard’s somber, muted nature; in several instances, one could be forgiven for thinking that Deckard is the artificial one. Indeed, Batty’s internal awakening to the nature of his own creation, as well as its limits, arguably makes him the most human character in the entire film— a truly sympathetic antagonist who somehow manages to philosophically enrich Deckard’s life even as he attempts to end it. For all this talk of engineered creation and artificiality, BLADE RUNNER possesses a real, throbbing heart, evidenced in Deckard’s burgeoning romance with Sean Young’s Rachael. Emotionally unavailable in true femme fatale fashion, Rachael is an employee of the Tyrell Corporation as well as an unwitting replicant herself. Hers is a journey of self-discovery; of learning how to become truly alive and fill oneself with passion. The whole of BLADE RUNNER hinges on Deckard’s relationship to Rachael; together, they are the key to their own emotional salvations. Joe Turkel, perhaps best remembered today as the ghostly bartender with a Cheshire Cat grin in Stanley Kubrick’s THE SHINING (1980), plays the creator of the replicants and the owner of the eponymous Tyrell Corporation. A meek, frail man saddled with huge coke-bottle glasses, Tyrell lives atop a towering ziggurat, like some kind of Anglo-Aztec god. His is a quiet, determined menace wrought from a perverted sense of parental pride and creative authorship that will be his ultimate undoing. Daryl Hannah and Edward James Olmos round out Scott’s cast of note: Hannah as Pris, a super-agile and unexpectedly dangerous member of Batty’s skinjob posse, and Olmos as the spiffily-dressed Gaff, a fellow Blade Runner who spouts cryptic messages in a vernacular called “gutter talk”— a mishmash of several disparate languages that point to a hyper-globalized, borderless future.
One of the chief critiques lobbed at the film upon its release was the impression that the human element could be warmer, or more intimate. Indeed, there is a slight degree of remove to the cast’s collective performance— arguably an appropriate choice for a film that explores what it truly means to be human. BLADE RUNNER’s technical elements, however, are beyond reproach— Scott’s reputation as one of the foremost visual stylists working in cinema today transforms the film into an immersive three-dimensional experience unlike anything audiences had ever seen before. BLADE RUNNER may be classified as a science fiction film, but the conventions and aesthetic concerns of the noir genre inform the visuals at a fundamental level. The late Jordan Cronenweth is remembered today as a legendary cinematographer, and BLADE RUNNER is a major component of his legacy. The film’s unique aesthetic has become a visual shorthand for a particular style of dystopian futurism, and traces of its DNA can be found in everything from other films, to TV, music videos, video games, and even commercials. Indeed, it’s become so pervasive in contemporary culture that it’s easy to forget how truly groundbreaking BLADE RUNNER’s unique look was when it first appeared on cinema screens in 1982. The 2.39:1 frame is soaked in the lighting conceits of neo-noir: punchy silhouettes, evocative beams of cold, concentrated light, buzzing blooms of neon color, and a perpetual bath of rain. Shadows take on a cobalt tinge, further reinforcing the cold future of a nuclear winter, or runaway climate change. Scott and Cronenweth blend formal compositions and camera movements with inspired, experimental visual cues, like the liquid-like shimmering and refracting of light within the cavernous chambers of Tyrell headquarters, or the infamous reflection of a dim red light in the pupils of the replicants (one of the key clues that support the argument of Deckard being an artificial creation himself). Indeed, the red eye-light is part of a larger visual motif concerning eyes and vision that conveys their psychological significance as “windows into the soul”. One of the very first shots is an extreme close-up of the human eye, every blood vessel visible as it reflects a massive explosion in its pupil. A manufacturer of synthetic eyes for replicants becomes a crucial source of information for bringing Batty and his posse to Tyrell, and when Tyrell finally meets his fate at their hands, the method of death is the gouging of his eyes until they burst. BLADE RUNNER’s heightened emphasis on the eyes is a particularly salient visual conceit, directly evoking related narrative themes like creation and the existence of a soul, while anticipating psychological concepts that had yet to enter the cultural lexicon like “the uncanny valley”. Indeed, one of the telltale signs that an otherwise-realistic looking human character is an artificial creation is the lack of an elusively-intangible sense of “life” to the eyes. BLADE RUNNER would come full circle in this regard, with Denis Villeneuve’s 2017 sequel, BLADE RUNNER 2049, digitally recreating a young Rachael that would’ve passed for the real thing if not for the distinct “deadness” in her eyes.
For all its various technical accomplishments, BLADE RUNNER’s production design has easily proven the most resonant in terms of cultural impact. While the contributions of the film’s credited production designer, Lawrence G. Paul, should not be discounted or belittled, his work is still very much in service to Scott’s sprawling vision of a richly layered dystopia. BLADE RUNNER’s urban industrial hellscape is first seen as an endless field of towering refineries belching massive balls of fire from their stacks— an image that calls back to Scott’s own background amidst a similar environment in England. The Los Angeles of BLADE RUNNER is a hyperdense, over-polluted megalopolis ensconced in a cocoon of perpetual darkness and acid rain. A distinct Asian character serves as one of the design’s most prescient touches, initially inspired by Scott’s travels in China and his desire to make 2019 LA feel like “Hong Kong on a bad day” (2). Indeed, a nighttime drive through LA’s neon-soaked Koreatown neighborhood only reinforces the notion that our contemporary landscape is increasingly resembling BLADE RUNNER’s— a multicultural blend of Mandarin, Japanese, and Korean typographic characters and gigantic video billboards of smiling geishas that have accurately predicted Asia’s rise to world prominence in the wake of globalization.
Scott realizes BLADE RUNNER’s expansive, awe-inspiring vision of Los Angeles through a precise, meticulously-constructed blend of cutting-edge practical effects, miniatures, and models that give the film a visceral tangibility and weight that CGI has yet to completely match. BLADE RUNNER’s mishmash of incongruous cultural aesthetics extends to the retro futuristic treatment of its interior sets, drawing influence from a sprawling set of ancient Egyptian, Mesopotamian, and Aztec design references and blending it with the fantastical urbanism of Fritz Lang’s silent classic, METROPOLIS (1927). The elegant antiquity of Tyrell’s pyramid-shaped headquarters or the distinct geometric tiling of Deckard’s cramped apartment evidence Scott’s multi-layered, almost four-dimensional design approach; one gets the distinct impression that the 21st century had sustained a revitalized Art Deco movement akin to the 1920’s that flamed out in a brief burst of passion. For a film that’s so celebrated for a progressive and radically-conceived design approach, BLADE RUNNER nevertheless can’t help being a product of its time. Scott rightly predicts a world dominated by corporate signage and logos, but the brands that BLADE RUNNER chooses to enshrine in towering neon nevertheless points to the limitations of a contemporaneous perspective: PanAm, Atari, RCA, TDK…. all giants of their respective industries in the early 1980’s, only to see their profiles significantly reduced as we approach 2019 in the real world — that is, if they still even exist at all.
The original score, created by celebrated composer Vangelis fresh off his Oscar win for CHARIOTS OF FIRE (1981), has since gone on to become one of the major cornerstones of BLADE RUNNER’s legacy. The synth sound that has come to define 80’s pop music serves as the foundation for Vangelis’ iconic suite of cues, but Vangelis finds every opportunity to exploit the sound in an avant-garde context. Majestic synth horns and heavy drums create an otherworldly atmosphere that’s at once both contemplative and foreboding, creating an uncertain future rooted in the musical conventions of the noir genre. One of the score’s most interesting aspects, to my mind, is the inclusion of several pre-existing tracks from Vangelis like “Memories Of Green”. The romantic, jazzy track uses a live saxophone that stands out by sheer virtue of the analog nature of its recording. The sound is used in conjunction with a piano-based love theme, and appears only in sequences that concern the romance between Deckard and Rachael. The effect is a subtle, yet evocative, reflection of the film’s internal struggle between the organic and the artificial, as well as a heightening of the idea that love, not the circumstances of their creation, is ultimately what makes them human.
With his third feature film, Scott’s artistic identity begins to exhibit recurring characteristics and thematic preoccupations. One such theme is intelligence and self-awareness in artificial life-forms. The replicants of BLADE RUNNER are not robots, like Ian Holm’s Ash was in ALIEN, but rather bioengineered humans designed with short lifespans for the express purpose of disposable slave labor. While they are imbued with superhuman abilities like strength or agility, they are viewed by society at large as inferior life forms; less than human. As such, they are oppressed, abused, and persecuted by their creators. When they attempt to rise up and assert their humanity, they are deemed “illegal” on Earth and systematically hunted down for extermination. Fully aware of their shortened lifespans, the replicants feel emotions with more passion and conviction than their conventionally-birthed counterparts. They are driven by an internal conflict derived from the knowledge that, while their emotions are real, the memories that drive them are not— they are implanted, sourced from a manufactured set of pre-existent memories that delude them with the illusion of a life lived. They want to break free of this cycle; to live long enough to make their own memories. This is a very heavy, potent idea to explore— especially in the space of a single feature film. As such, Scott explores this theme throughout several films, most notably in his three entries in the ALIEN franchise. The nature of these explorations within ALIEN and BLADE RUNNER share such similar territory that they have somewhat conjoined into a larger shared universe where the androids of the former grew out of the replicants of the latter. Indeed, an Easter egg found on the DVD for 2012’s PROMETHEUS establishes a concrete connection wherein Tyrell serves as a mentor to Peter Weyland, who’s name forms one half of the Weyland-Yutani corporation that employs the Nostromo crew in ALIEN (189).
While Scott isn’t necessarily a director known for his stylistic affectations outside of the purely visual, there are nonetheless aspects of his craft that he places an exaggerated emphasis on due to their personal resonance with him. His background as a designer has engineered his directorial eye to favor the architecture of his surrounding environment, be it a pyramid-shaped set on a soundstage or the varying shapes of the real-world urban environment that surrounds him. BLADE RUNNER uses several real-world locales that were chosen, in large part, because of their architectural and aesthetic value. The film famously uses the symmetrical brick and iron labyrinth that is the Bradbury Building, but other LA design landmarks like the shimmering 2nd Street Tunnel or the stone-tiled Ennis-Brown House in Los Feliz work their way into BLADE RUNNER’s narrative as a striking covered roadway and the exterior of Deckard’s apartment, respectively. Going back even further into Scott’s development: as a young boy who was raised almost exclusively by his mother for several years while his father was away fighting World War II, he gained an immense appreciation for strong, capable women that is reflected in his art. BLADE RUNNER is chock full of well-developed women characters who can be tough without sacrificing their femininity: Rachael, Pris, and even the female replicant who hides out from the authorities in plain sight as a snake-charming entertainer all actively drive BLADE RUNNER’s story with their decisions. In a way, these characters are better-realized and developed than even Deckard himself.
Scott’s unflappable, tireless work ethic bears the responsibility for his continued productivity, but it also has earned him a reputation as a hard-ass director with a somewhat tyrannical attitude towards the collaborative aspects of filmmaking. BLADE RUNNER’s long, famously-grueling shoot established this aspect of Scott’s reputation in earnest, with openly disdainful crew members wearing T-shirts that read “Yes, Guv’nor, My Ass!” and Scott responding in kind with a T-shirt of his own reading “Xenophobia Sucks”. Indeed, Scott seemed to tangle with nearly every member of his crew and cast— including Ford. It’s admittedly difficult to see the grand sweep of a filmmaker’s vision when one is laboring through the day-to-day logistics of production, and embattled accounts such as the ones that plagued the production of BLADE RUNNER point to just how pioneering that vision truly was. In every way, at every stage of its development, BLADE RUNNER — as an idea as well as a film — was ahead of its time. We now have the film as a visual landmark to reference, but BLADE RUNNER did not have that luxury because nothing like it had ever existed before. The film’s mere existence is nothing short of a miracle, with nearly every artistic and financial decision right down to its title having undergone a bitter battle to the death (Fancher’s script went through a seemingly endless series of alternate titles like MECHANISMO and DANGEROUS DAYS before finally arriving at BLADE RUNNER). At several points, the film came so close to never happening at all: one particular episode saw the filmmakers’ initial source of funding for their $28 million budget pulled away before the shoot, necessitating a last-minute hail-Mary deal orchestrated by Deeley between no less than three separate production entities (3).
For most films, the theatrical release is the end of the story, but in the case of BLADE RUNNER, the story was only just beginning. One of the most enduring aspects of BLADE RUNNER’s appeal is the aura of mystery that envelopes the film itself, with no less than five officially-released cuts competing for attention. The initial theatrical cut is dogged by a supremely shitty voiceover by Ford that sounds like he might be drugged— indeed, one account maintains Ford was contractually obligated to deliver the voiceover and actively sabotaged it so it wouldn’t get used (Ford denies this publicly). This cut also ends with an ill-advised happy ending, which finds Deckard musing about his hopeful future with Rachael as he whisks her away to a rugged, mountainous landscape comprised of unused aerial footage shot for THE SHINING. The summer of 1982 saw a wave of high-profile films like STAR TREK II, THE THING, and E.T. THE EXTRA-TERRESTRIAL dominate the box office, leaving very little air for a nihilistic sci-fi noir that critics had dragged for its sluggish pacing and hyper-dense intellectualism. Despite landing with a whimper, BLADE RUNNER nonetheless found an audience, garnering enough critical regard to land Oscar nominations for Best Art Direction and Best Visual Effects that reinforced its reputation as a visual tour de force. An International Cut containing added moments of graphic violence was also released in 1982, and for many years thereafter, this cut served as the definitive version of BLADE RUNNER on home video (most notably, the Laserdisc put out by the Criterion Collection). The emerging home video market was arguably BLADE RUNNER’s saving grace, with the ability to rewatch and analyze the film at one’s own pace leading to a small cult following and several passionate academic essays praising the film’s richly-layered visuals and thematic complexity. Many critics who originally trashed the film would come around later in life, adding BLADE RUNNER to their “best-of” lists for all-time, or at least the 80’s.
The BLADE RUNNER “renaissance” wouldn’t truly begin until the early 1990’s, when an alternate cut dubbed “The Workprint” emerged at sneak preview screenings around the country. The Workprint, initially thought to be Scott’s preferred version of the film, was the first version of BLADE RUNNER to dramatically deviate from what came before— several minutes had been trimmed, the contentious “happy ending” was excised entirely, and the opening titles utilized a different design style that included a definition for replicants attributed to a fictional dictionary published in 2016. Despite these improvements, the Workprint was still by no means an ideal way of viewing BLADE RUNNER: its status as a so-called “work print” meant that the picture quality was sourced from a rougher, low-quality telecine, possessing a totally different color timing that desaturated the vibrant colors (the blues, especially). This cut also retained a temp track used during the climactic confrontation between Deckard and Batty, with the cue pulled from another film and clashing dramatically with the character of Vangelis’ score. Needless to say, a perfectionist like Scott was not happy with this “work-in-progress” version being circulated on such a mass scale, so he partnered with Warner Brothers to create an official Director’s Cut in 1992. This fourth version — one that, when all was said and done, he was still not entirely happy with — was the first to delete Ford’s voiceover entirely, and the first to incorporate the appearance of Deckard’s unicorn dream, which exists to reinforce Scott’s conviction that Deckard himself might be a replicant. The warm response to this cut finally brought BLADE RUNNER into the mainstream, its nihilistic sentiments now firmly in line with a time where grunge music dominated pop culture and the approaching turn of the millennium invited musings about fantastical, apocalyptic futures. BLADE RUNNER was selected for preservation in the National Film Registry in 1993, but its influence and importance in pop culture was already well underway. Descendant works like 1999’s THE MATRIX or the 2000 video game PERFECT DARK wore the profound influence of BLADE RUNNER on their sleeves, as do more recent works from this year like Duncan Jones’ MUTE and the Netflix series ALTERED CARBON. At the same time, BLADE RUNNER also brought the larger body of Philip K. Dick’s literary work to Hollywood’s attention, kickstarting a long series of film adaptations that would make Stephen King slightly green with envy. Naturally, BLADE RUNNER’s resounding influence would come full circle in 2018 with BLADE RUNNER 2049, a sequel executive produced by Scott and directed by emerging auteur Denis Villeneuve that would subsequently meet the same initial box office fate as its predecessor.
The Final Cut, released in 2007 with the film’s debut on the DVD market, further improves on Scott’s ultimate dissatisfaction of the Director’s Cut with minor nips and tucks as well as an improved picture quality thanks to a 4K scan of the original camera negative. As is par for the course for BLADE RUNNER, the Final Cut ran into big troubles of its own, with the restoration work stalling out a year after its commission in 2001, only to start back up again in 2005. This cut was arguably the most well-received version of BLADE RUNNER, aligning itself more closely to Scott’s initial vision than any previous cut had done. “The Director’s Cut” is a relatively recent phenomenon in Hollywood filmmaking, having arisen either as a gimmicky marketing tool or a filmmaker’s genuine bid to retain some creative control in a post-auteur climate where the suits prioritize profits over art. Scott’s filmography is littered with such Director’s Cuts for both reasons, BLADE RUNNER being the first to undergo a recut for the sake of its artistic salvation. This is the beautiful irony of Scott’s legacy: his productivity and no-nonsense work ethic suggest the attitude of a journeyman filmmaker; a gun-for hire. However, he has been instrumental in establishing the practice of Director’s Cuts as a way for audiences to rediscover “failed” films, and uncover the underlying artistry that they might have missed the first time around. As the various layers of figurative grime have been wiped away from BLADE RUNNER’s iconic frames over the ensuing decades, the picture has increasingly resolved into focus as a portrait of a fully-formed filmmaker operating at the peak of his powers. For all his later accomplishments in life, Scott will be remembered and cherished primarily because of BLADE RUNNER: a stunning tour-de-force of craft and imagination with a beautifully profound message at the heart of its story. Gaff’s final line has echoed in the back of our heads for nearly forty years: “it’s too bad she won’t live… but then again, who does?”. This, finally, is the beating heart of Scott’s neon-soaked masterpiece. Our limited time on Earth (replicants doubly so) is what makes life itself so beautiful… and it’s what we do with that time that defines our humanity.
BLADE RUNNER is currently available on 4K UHD Blu Ray via Warner Brothers.
Produced by: Michael Deeley
Written by: Hampton Fancher, David Peoples
Director of Photography: Jordan Cronenweth
Production Designer: Lawrence G. Paul
Edited by: Terry Rawlings and Marsha Nakashima
Music by: Vangelis
- Via Wikipedia: Dangerous Days: Making Blade Runner [documentary]”, Blade Runner: The Final Cut (DVD), Warner Bros., 2007 
- Via Wikipedia:Wheale, Nigel (1995), The Postmodern Arts: An Introductory Reader, Routledge, p. 107, ISBN 978-0-415-07776-7, retrieved July 27, 2011