U. Schippmann

Progress on the International Standard for Sustainable Wild Collection of Medicinal and Aromatic Plants (ISSC-MAP).

B. Pätzold, S. Honnef, D. Leaman, 2005 .

Impact of cultivation and gathering of medicinal plants on biodiversity: global trends and issues.

U. Schippmann, A. B. Cunningham, Danna J. Leaman, 2003 .