El-Sharief, A. M. Sh.; Ammar, M. S.; Ammar, Y. A.; Zaki, M. E. A.
Indian Journal of Chemistry, Section B: Organic Chemistry Including Medicinal Chemistry, 1983 , vol. 22, # 7 p. 700 - 704

SRI International
Patent: US4218465 A1, 1980 ;