APA (7th ed.) Citation

Wagner, R., Mathieu, E., Dupuis, S., Biarent, A., Andersen, D., & Delcour, P. Wagnerian songs.

Chicago Style (17th ed.) Citation

Wagner, Richard, Emile Mathieu, Sylvain Dupuis, Adolphe Biarent, Diane Andersen, and Patrick Delcour. Wagnerian Songs.

MLA (9th ed.) Citation

Wagner, Richard, et al. Wagnerian Songs.