Structures of polygalacin D and D2, platycodin D and D2 and their monoacetates, saponins isolated from Platycodon grandiflorum A. D.C., determined by 13C nuclear magnetic resonance spectroscopy - Ishii,H.; Tori,K.; Tozyo,T.; Yoshimura,Y. (Chem. Pharm. Bull., 1978)