Morvern Callar was the debut novel by Scottish author Alan Warner, first published in 1995.
One of the first English guys Morvern and Lanna meet says he knows a certain Alwin Küchler from Germany. Alwin Küchler is the German cinematographer of this film.
James Gillespie (Morvern's boyfriend) is also the name of the protagonist from Ramsay's previous movie, Ratcatcher (1999).