1. The taxonomy of the genus Echinacea (Compositae);McGregor;Univ Kansas Sci Bull,1968
2. Medicinal properties of Echinacea: a critical review;Barrett;Phytomedicine,2003
3. Echinacea species as potential immunostimulatory drugs;Bauer,1991
4. Echinacea stimulates macrophage function in the lung and spleen of normal rats;Goel;J Nutr Biochem,2002
5. Echinacea standardization: analytical methods for phenolic compounds and typical levels in medicinal species;Perry;J Agric Food Chem,2001