APA (7th ed.) Citation

Gay, K., & Gay, M. (1995). Spanish-American War. Twenty-First Century Books.

Chicago Style (17th ed.) Citation

Gay, Kathlyn, and Martin Gay. Spanish-American War. New York: Twenty-First Century Books, 1995.

MLA (9th ed.) Citation

Gay, Kathlyn, and Martin Gay. Spanish-American War. Twenty-First Century Books, 1995.