Shridhar, D.R.; Jogibhukta, M.; Joshi, P. P.; Reddy, P. Gopal
Indian Journal of Chemistry, Section B: Organic Chemistry Including Medicinal Chemistry, 1981 , vol. 20, # 2 p. 132 - 134

Arndt, Friedrich; Franke, Wilfried; Klose, Walter; Lorenz, Joerg; Schwarz, Katica
Liebigs Annalen der Chemie, 1984 , # 7 p. 1302 - 1307