REFERENCES
- Bauer , R. , Remiger , P. and Wagner , H. 1988 . Alkamides from the roots of . Echinacea purpurea. Phytochemistry , 27 ( 7 ) : 2339 – 2342 .
- Bauer , R. and Remiger , P. 1989 . TLC and HPLC analysis of alkylamides of Echinacea drug. . Planta Medica , 55 : 367 – 371 .
- Bauer , R. and Wagner , H. 1991 . “ Echinacea species as potential immunostimulatory drugs ” . In Economics and Medicinal Plant Research Edited by: Wagner , H. , Hikino , H. and Farnsworth , N. R. Vol. 5 , 253 – 321 . London : Academic Press .
- Black , C. A. 1965 . “ Methods of Soil Analysis Part 2 ” . In Chemical and Microbiological Properties. Madison, Wisconsin, , U.S.A. : American Society of Agronomy, Inc. .
- Heinzer , F. , Meusy , J. P. and Chavanne , M. 1988 . “ Echinacea pallida Echinacea purpurea; follow up of weight development and chemical composition for the first two culture years ” . In Abstracts of 36th Annual Congress of the Society of Medicinal Plant Research. September, 1988. Freiburg, Germany
- Shalaby , A. S. , El-Gengaihi , S. E. , Agina , E. A. , El-Khayat , A. S. and Hendawy , S. F. 1997 . Growth and yield of Echinacea purpura L. as influenced by planting density and fertilization. . J. Herbs, Spices & Medicinal Plants , 5 ( 1 ) : 69 – 76 .