1. L. Jansen,Some Aspects of Molecular Interactions in Dense Media(Martinus Nijhoff, The Hague, Netherlands, 1955).
2. M. H. Rice, R. G. McQueen, and J. M. Walsh,Solid State Physics, edited by F. Seitz and D. Turnbull (Academic Press Inc., New York, 1958), Vol. 6.