Found a quote, had to use the anglicized spelling though.

https://www.vanityfair.com/culture/2011/08/heller-201108

"The Czech writer Arnošt Lustig claimed that Heller had told him at a New York party for Milos Forman in the late 1960s that he couldn’t have written Catch-22 without first reading Jaroslav Hašek’s unfinished World War I satire, The Good Soldier Schweik. "