1. Fukada, E., Bull. Kabayashi Inst. Phys. Res., 9, 45 (1959).
2. Rez, I. S., Kristallografia, 6, 646 (1961); Soviet Phys.-Crystallog., 6, 521 (1962).
3. Fukada, E., J. Phys. Soc. Japan, 10, 149 (1955).
4. Bazhenov, U. A., Piezoelectric Properties of Wood (Consultants Bureau, New York, 1961).
5. Galligan, N. L., and Bertholf, L. D., Forest Prod. J., 13, 517 (1963).