1. H. Matsumoto, J. Phys. Soc. Japan 20, 1579 (1965).
2. T. Iri and G. Kuwabara, J. Phys. Soc. Japan 24, 127 (1968) and references therein.
3. T.E. Freeman and G. D. Jones (to be published).
4. R.W.G. Wyckoff, “Crystal Structures,” 1, Interscience Publishers, New York, 1964.
5. S. Bhagavantam and T. Venkatarayudu, “Theory of Groups and Its Application to Physical Problems,” Andhra University, Waltair, India, 1951.