APA (7th ed.) Citation

Thonner, F., & Geesink, R. (1981). Thonner's analytical key to the families of flowering plants. PUDOC.

Chicago Style (17th ed.) Citation

Thonner, Franz, and R. Geesink. Thonner's Analytical Key to the Families of Flowering Plants. Wageningen: PUDOC, 1981.

MLA (9th ed.) Citation

Thonner, Franz, and R. Geesink. Thonner's Analytical Key to the Families of Flowering Plants. PUDOC, 1981.