Question: Of directors William Blake Herron and Peter Sasdy, who contributed to the screenplay for "The Bourne Identity"?

Context articles: Nothing but the Night
The Bourne Supremacy (film)
Peter Sasdy
The Bourne Identity (1988 film)
The Bourne Identity (novel)
William Blake Herron
The Bourne Ultimatum (film)
The Bourne Legacy (film)
Doomwatch (film)
The Bourne Identity (2002 film)

Nothing But the Night is a 1973 British horror film directed by Peter Sasdy, starring Christopher Lee and Peter Cushing.
The Bourne Supremacy is a 2004 American-German action spy thriller film starring Robert Ludlum's Jason Bourne character.
 Though it takes the name of the second Bourne novel, its plot is entirely different.
 The film was directed by Paul Greengrass from a screenplay by Tony Gilroy.
 Universal Pictures released the film to theaters in the United States on July 23, 2004.
 It is the second in the "Jason Bourne" film series.
 It is preceded by "The Bourne Identity" (2002) and followed by "The Bourne Ultimatum" (2007), "The Bourne Legacy" (2012), and "Jason Bourne" (2016).
Peter Sasdy (born 27 May 1935 in Budapest, Hungary) is a Hungarian-born British film and television director.
The Bourne Identity is a 1988 American mystery thriller television movie adaptation of Robert Ludlum's novel "The Bourne Identity".
 The film adaptation was written by Carol Sobieski, directed by Roger Young for Warner Bros.
 Television with Richard Chamberlain in the title role, along with Jaclyn Smith.
 It follows the storyline of the original novel, with a run-time of 3 hours 5 min.
 With commercials added, the running time was extended to four hours.
 The film was first shown on ABC in two two-hour installments over two nights.
 The film was the last TV film for both Anthony Quayle and Denholm Elliott.
The Bourne Identity is a 1980 spy fiction thriller by Robert Ludlum that tells the story of Jason Bourne, a man with remarkable survival abilities who suffers from retrograde amnesia, and must seek to discover his true identity.
 In the process, he must also reason out why several shadowy groups, a professional assassin, and the CIA want him dead.
 The story takes readers on an action-packed journey into a world of deceptions and conspiracies, offering a psychological portrait of Bourne, and giving them the chance to experience from his point of view the life-or-death decisions he makes as he seeks to piece together the dangerous puzzle of his missing past.
 It is the first novel of the original Bourne Trilogy, which also includes "The Bourne Supremacy" and "The Bourne Ultimatum".
William Blake Herron is a film screenwriter, director and actor who contributed to the screenplay for "The Bourne Identity".
 He also contributed to the screenplay for "Eye of the Widow".
The Bourne Ultimatum is a 2007 American-German action spy thriller film directed by Paul Greengrass loosely based on the novel of the same name by Robert Ludlum.
 The screenplay was written by Tony Gilroy, Scott Z. Burns and George Nolfi and based on a screen story of the novel by Gilroy.
 "The Bourne Ultimatum" is the third in the "Jason Bourne" film series, being preceded by "The Bourne Identity" (2002) and "The Bourne Supremacy" (2004).
 The fourth film, "The Bourne Legacy", was released in August 2012, without the involvement of Damon, and the fifth film (a direct sequel to "Ultimatum"), "Jason Bourne", was released in July 2016.
The Bourne Legacy is a 2012 American action thriller film directed by Tony Gilroy, and is the fourth installment in the series of films adapted from the "Jason Bourne" novels originated by Robert Ludlum and continued by Eric Van Lustbader, being preceded by "The Bourne Identity" (2002), "The Bourne Supremacy" (2004), and "The Bourne Ultimatum" (2007).
 Although this film has the same title as Van Lustbader's first "Bourne" novel, "The Bourne Legacy", the actual screenplay bears little resemblance to the novel.
 Unlike the novel, which features Jason Bourne as the principal character, the film centers on black ops agent Aaron Cross (played by Jeremy Renner), an original character.
 In addition to Renner, the film stars Rachel Weisz and Edward Norton.
Doomwatch (US title: Island of the Ghouls) is a 1972 science fiction/thriller film directed by Peter Sasdy.
 The film is based on the BBC series "Doomwatch".
 The screenplay was written by Clive Exton.
The Bourne Identity is a 2002 action spy thriller film based on Robert Ludlum's novel of the same name.
 It stars Matt Damon as Jason Bourne, a man suffering from extreme memory loss and attempting to discover his true identity amidst a clandestine conspiracy within the Central Intelligence Agency (CIA).
 The film also features Franka Potente, Chris Cooper, Clive Owen, Julia Stiles, Brian Cox and Adewale Akinnuoye-Agbaje.
 The first in the "Jason Bourne" film series, it was followed by "The Bourne Supremacy" (2004), "The Bourne Ultimatum" (2007), "The Bourne Legacy" (2012) and "Jason Bourne" (2016).