1. “The Merck Index” 11th Edition, p. 971 (1989).
2. “Clarks' Isolation and Identification of Drugs”,1986
3. “The Extra Pharmacopeia”,1989
4. “British Pharmacopeia”,1988
5. Mohammad A. Abounassif and Mohammad Saleem Mian, Unpublished Data, College of Pharmacy, King Saud University, 1991.