Proudfoot, John R.; Li, Xian; Djerassi, Carl
Journal of Organic Chemistry, 1985 , vol. 50, # 12 p. 2026 - 2030

Nes, W. David; McCourt, Brian S.; Marshall, Julie A.; Ma, Jianzhong; Dennis, Allen L.; Lopez, Monica; Li, Haoxia; He, Ling
Journal of Organic Chemistry, 1999 , vol. 64, # 5 p. 1535 - 1542