APA (7th ed.) Citation

Wagner, C., Gregor-Dellin, M., Mack, D., & Skelton, G. (1978). Cosima Wagner's Diaries. Harcourt Brace Jovanovich.

Chicago Style (17th ed.) Citation

Wagner, Cosima, Martin Gregor-Dellin, Dietrich Mack, and Geoffrey Skelton. Cosima Wagner's Diaries. New York: Harcourt Brace Jovanovich, 1978.

MLA (9th ed.) Citation

Wagner, Cosima, et al. Cosima Wagner's Diaries. Harcourt Brace Jovanovich, 1978.