Koh Hwee Ling, Chua Tung Kian, and Tan Chay Hoon. "A Guide to Medicinal Plants: An Illustrated, Scientific and Medicinal Approach", p. 14. World Scientific Publishing 2009, ISBN 981-283-709-4. Preview available at Google Books http://books.google.com.
Wiart, Christophe. "Medicinal Plants of Asia and the Pacific", p. 56. CRC Press 2006, ISBN 0-8493-7245-3. Preview available at Google Books http://books.google.com.