Systematics, evolution, and taxonomic categoriesFriedrich Ehrendorfer, Erich Kessler, G. Ledyard Stebbins, R. D. Hoogland, L. A. S. Johnson, Willard W. Payne, Theodore J. Crovello · First published 1976Open the Tome
A re-evaluation of the genus Ambrosia (Compositae)Willard W. Payne · First published 1964Open the Tome
