Tyler's Honest Herbal, fourth edition (The Hawthorn Herbal Press) by Steven Foster and Varro E. Tyler, Ph.D.

The Green Pharmacy (Rodale Press) by James A. Duke, Ph.D.

Physician's Desk Reference for Herbal Medicines (Medical Economics Company)

The Complete German Commission E Monographs: Therapeutic Guide to Herbal Medicines (American Botanical Council) edited by Mark Blumenthal, et al.

The Foundations of Health: Healing with Herbs & Foods (Botanica Press) by Christopher Hobbs