Joseph Heller claimed he would have never written it had he never read The Good Soldier Švejk.
From https://www.nytimes.com/2004/11/17/theater/newsandfeatures/t...
"Heller, who died in 1999, told various interviewers that Céline and Kafka were his most powerful influences and that "Svejk" was "just a funny book.""
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. "