APA (7th ed.) Citation

Hawks, E., & Boulger, G. S. (1969). Pioneers of plant study. Books for Libraries Press.

Chicago Style (17th ed.) Citation

Hawks, Ellison, and G. S. Boulger. Pioneers of Plant Study. Freeport N.Y.: Books for Libraries Press, 1969.

MLA (8th ed.) Citation

Hawks, Ellison, and G. S. Boulger. Pioneers of Plant Study. Books for Libraries Press, 1969.