APA (7th ed.) Citation

Stefan-Gruenfeldt, P., & Paul, E. (1938). Arturo Toscanini. Blue Ribbon Books.

Chicago Style (17th ed.) Citation

Stefan-Gruenfeldt, Paul, and Eden Paul. Arturo Toscanini. New York: Blue Ribbon Books, 1938.

MLA (9th ed.) Citation

Stefan-Gruenfeldt, Paul, and Eden Paul. Arturo Toscanini. Blue Ribbon Books, 1938.