TY - JOUR AU - Sarkar, A; Okada, S; Nakanishi, H; Matsuda, H JO - Helv. Chim. Acta VL - 82 PY - 1999 DO - 10.1002/(SICI)1522-2675(19990113)82:1<138::AID-HLCA138>3.0.CO;2-G SP - 138 ER -