Gaya APA

Skillicorn, H., Samuelsson, G. (1999). Drugs Of Natural Origin (a Textbook Of Pharmacognosy) (4th Ed.). Stockholm: Swedish Pharmaceutical Press.

Gaya MLA

Skillicorn, Helen., Samuelsson, Gunnar. "Drugs Of Natural Origin (a Textbook Of Pharmacognosy)". 4th Ed. Stockholm: Swedish Pharmaceutical Press, 1999. Text.