APA (7th ed.) Citation

Smolian, A., Pfohl, F., & Merian, H. (1900). Richard Wagners Opern. Schlesinger.

Chicago Style (17th ed.) Citation

Smolian, Arthur, Ferdinand Pfohl, and Hans Merian. Richard Wagners Opern. Berlin: Schlesinger, 1900.

MLA (9th ed.) Citation

Smolian, Arthur, et al. Richard Wagners Opern. Schlesinger, 1900.