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K. Sugihara:Journ. Phys. Soc. Japan,14, 1231 (1959).
L. K. Aminov andB. I. Kochelaev:Sov. Phys. JETP,15, 903 (1962).
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R. Orbach andM. Tachiki:Phys. Rev.,158, 524 (1967).
J. M. Baker andA. E. Mau:Canad. Journ. Phys.,45, 403 (1967).
R. J. Anderson, J. M. Baker andR. J. Birgenau:Journ. Phys. C,4 1618 (1971).
J. M. Baker:Journ. Phys. C,4, 1631 (1971).
P. O. Lowdin:Journ. Chem. Phys.,19, 1396 (1951).
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E. Borchi, S. De Gennaro andM. Mancini:Nuovo Cimento,61 B, 241 (1969).
J. A. A. Ketelaar:Physica,4, 619 (1937).
A. J. Freeman andR. E. Watson:Phys. Rev.,127, 2058 (1962).
G. Burns:Journ. Chem. Phys.,42, 377 (1965).
J. C. Hill andR. G. Wheeler:Phys. Rev.,152, 482 (1966).
