1. M. Cardona, “Solid State Physics,” Suppl. 11, edited by F. Scitz, D. Turnbull, and H. Ehrenreich (Academic, New York 1969).
2. “Semiconductors and Semimetals” edited by R. L. Willardson and A. C. Beer (Academic, New York, 1972, Vol. 9).
3. Proc. of the First Int. Conf. on Modulation Spectroscopy, 1972 [Surface Science37 (1973)].
4. D. E. Aspnes in “Handbook on Semiconductors,” Vol. 2 on “Optical Properties of Solids” edited by M. Balkanski, (North-Holland, New York 1980).
5. E. Y. Wang and W. A. Albers, Phys. Lett.27A, 347 (1968).