1. S. Kitamura and G. Murata, “Coloured Illustrations of Woody Plants of Japan,” Vol. II, Hoikusha Pub. Co., Ltd., Tokyo, 1979, p. 220.
2. E. Stenhagen, S. Abrahamsson and F. W. McLafferty, “Registry of Mass Spectral Data,” John Wiley, New York, 1974.