APA (7th ed.) Citation

Sawyer, R. (1986). Slavery in the twentieth century. Routledge & Kegan Paul.

Chicago Style (17th ed.) Citation

Sawyer, Roger. Slavery in the Twentieth Century. London [u.a.]: Routledge & Kegan Paul, 1986.

MLA (8th ed.) Citation

Sawyer, Roger. Slavery in the Twentieth Century. Routledge & Kegan Paul, 1986.