1. J. Zelmanov: J. Phy. USSR. 8, 135 (1944).
2. F. Srmon: Phys. Z. 34, 232 (1933).
3. W. H. Mcadams: Heat Transmission, pp. 128 and 174. New York: McGraw-Hill Company 1942
4. J. Gorrie: U.S. Patent 8080. 1851.
5. E. Solvay: C. R. Acad. Sci. Paris 121, 1141 (1895).