APA (7th ed.) Citation

Christensen, K. I. (1992). Revision of Crataegus Sect. Crataegus and Nothosect. Crataeguineae (Rosaceae-Maloideae) in the Old World. American Soc. of Plant Taxonomists.

Chicago Style (17th ed.) Citation

Christensen, Knud I. Revision of Crataegus Sect. Crataegus and Nothosect. Crataeguineae (Rosaceae-Maloideae) in the Old World. Ann Arbor, Mich: American Soc. of Plant Taxonomists, 1992.

MLA (9th ed.) Citation

Christensen, Knud I. Revision of Crataegus Sect. Crataegus and Nothosect. Crataeguineae (Rosaceae-Maloideae) in the Old World. American Soc. of Plant Taxonomists, 1992.