APA (7th ed.) Citation

Hall, A. D., & Osterstock, H. C. (1940). The genus Tulipa.

Chicago Style (17th ed.) Citation

Hall, Alfred D., and H. C. Osterstock. The Genus Tulipa. London, 1940.

MLA (9th ed.) Citation

Hall, Alfred D., and H. C. Osterstock. The Genus Tulipa. 1940.

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