1. F. H. Perrin, Usp. Fiz. Nauk,78, 307 (1962).
2. A. Bouwers, in: Selected Scientific Papers, Amsterdam (1969), pp. 578–588.
3. A. Bouwers, in: Selected Scientific Papers, Amsterdam (1969), p. 597–608.
4. R. Veenenga Kingma, I. Becker, and A. Y. Cuelenaera, Optik (Stuttgart),30, 419 (1970).
5. R. Reuther, Radiol. Diagn.,10, 355 (1969).