Lem, Stanislaw. "The Time-Travel Story and Related Matters of SF Structuring"
Comments: Discusses SF treatments of time-travel, paradox loops, and the chronocracy (including Bradbury's "A Sound of Thunder", W. Moore's Bring the Jubilee, and Asimov's The End of Eternity) in terms of the philosophical or historical inquiry present in the text.
Published: In Science-Fiction Studies vol. 1, pp. 143-154 (Spring 1974), Thomas H. Hoisington and Darko Suvin.