1. J. D. Henry, Jr, in: Recent Developments in Separation Science, vol. 2, p. 205. Ed. N. N. Li. CRC Press, Cleveland 1975.
2. A. Valeri, G. Gazzei, M. Morandi, B. Pende and P. Neri, Experientia33, 1402 (1977).
3. Code of Federal Regulations21, 51, paragraph 620.2 (1977).
4. Code of Federal Regulations21, 53, paragraph 620.5 (1977).