You can look at some of these different books as well as the abstracts in the Protocols section of LEF, for referances. 
Scientific Validation of Herbal Remedies. 
Mowrey D.
USA: Keats Publishing, 1990.
Herbal Tonic Therapies. 
Mowrey D.
USA: Keats Publishing, 1993.
Herbal Medicine. 
Weiss...