APA (7th ed.) Citation

Watt, W. M. (1968). What is Islam? (1. publ.). Longmans.

Chicago Style (17th ed.) Citation

Watt, William Montgomery. What Is Islam? 1. publ. London [u.a.]: Longmans, 1968.

MLA (9th ed.) Citation

Watt, William Montgomery. What Is Islam? 1. publ. Longmans, 1968.

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