Pages 397-431 in P. L. Fieldler and S. K. Jain, editors. Schemske, D. W., B. C. Husband, M. H. Ruckelshaus. C. Goodwillie, I. M. Parker and J. G. Bishop. Evaluating approaches to the conservation of rare and endangered plants. Stafford, R. 1989.
Botanists find cactus better neighbourhood.
The Centre for Plant Conservation. Thomas N. Kaye, Aaron Liston, Rhoda M. Love, Daniel L. Luoma, Robert J. Meinke, and Mark V. Wilson. With a foreword by Reed F. Noss, Oregon State University. Native Plant Society of Oregon. Soft cover only.