Tateiwa, Jun-Ichi; Uemura, Sakae
Bulletin of the Chemical Society of Japan, 1997 , vol. 70, # 7 p. 1615 - 1619

Rao,R.R. et al.
Indian Journal of Chemistry, Section B: Organic Chemistry Including Medicinal Chemistry, 1979 , vol. 18B, p. 117 - 121