Actor Viggo Mortensen is appealing to the descendants of Carl Jung to release more letters by the founder of analytical psychology.
Mortensen appears as Sigmund Freud in David Cronenberg's drama "A Dangerous Method," which focuses on Freud's relationship with his protege, Jung, played by Michael Fassbender.
Keira Knightley portrays Sabina Spielrein, the psychiatric patient-turned-analyst who comes between the two men. The film draws heavily on correspondence between the three historical figures.
Mortensen said before the movie's world premiere Friday that the letters between Jung and Spielrein are "very good reading" and that he'd like to see more. The movie is screening in competition at the Venice Film Festival.