APA (7th ed.) Citation

Taylor, A. J. P., & Bullock, A. (1979). 20th Century. Purnell Reference Books.

Chicago Style (17th ed.) Citation

Taylor, A. J. P., and Alan Bullock. 20th Century. Milwaukee [u.a.]: Purnell Reference Books, 1979.

MLA (9th ed.) Citation

Taylor, A. J. P., and Alan Bullock. 20th Century. Purnell Reference Books, 1979.