J. R. Reitz

Physics Physique Fizika 2, 205 (1966) - Published 1 May, 1966

H. L. Frisch

Physics Physique Fizika 2, 209 (1966) - Published 1 May, 1966

R. G. Shulman

Physics Physique Fizika 2, 217 (1966) - Published 1 May, 1966

W. E. Keller and E. F. Hammel

Physics Physique Fizika 2, 221 (1966) - Published 1 May, 1966