Complex sentence: The film is based on Frank Rooney's short story "The Cyclists' Raid", published in the January 1951 issue of "Harper's Magazine" and anthologized in "The Best American Short Stories 1952".
Split into simpler sentences: The film is based on Frank Rooney's short story "The Cyclists' Raid", which was published in the January 1951 issue of "Harper's Magazine". The story was later published in book form as part of "The Best American Short Stories 1952".