APA (7th ed.) Citation

Watt, W. M., & Welch, A. T. (1980). Der Islam. Der Islam.

Chicago Style (17th ed.) Citation

Watt, William Montgomery, and Alford T. Welch. "Der Islam." Der Islam 1980.

MLA (8th ed.) Citation

Watt, William Montgomery, and Alford T. Welch. "Der Islam." Der Islam, 1980.

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