Cytotoxic ent-kaurane diterpenoids from Isodon eriocalyx var. laxiflora - Niu,X.M.; Li,S.H.; Li,M.L.; Zhao,Q.S.; Mei,S.X.; Na,Z.; Wang,S.J.; Lin,Z.W.; Sun,H.D. (Planta Medica, 2002)