1. H. Bartels, Z. Phys.,125, 597, 1949;126, 108, 1949;127, 243, 1950;128, 546, 1950.
2. A. S. Dubovik, Photographic Recording of Fast Processes [in Russian], Izd. Nauka, Moscow, 1964.
3. A. E. Voitenko, F. O. Kuznetsov, and I. Sh. Model, PTE, no. 3, 121, 1962.
4. H. Fischer, JOSA,43, 394, 1953.
5. H. Bartels, Z. Phys.,136, 411, 1953.