APA (7th ed.) Citation

Asimov,Isaac. (1991). Foundation and empire. Bantam Books.

Chicago Style (17th ed.) Citation

Asimov,Isaac. Foundation and Empire. New York: Bantam Books, 1991.

MLA (9th ed.) Citation

Asimov,Isaac. Foundation and Empire. Bantam Books, 1991.

Warning: These citations may not always be 100% accurate.