1. Attmanspacher, W. and Riedl, J.: 1973,Ber. d. Deutsch. Wetterd. 131, Offenbach, W. Germany.
2. Braak, C.: 1945,KNMI Meded. en Verh. 48, The Hague, The Netherlands.
3. Chagnon, S. A. and Semonin, R. G.: 1975, Report of investigation 81, Illinois State Water Survey, Urbana.
4. Dawson, G. A.: 1978,Atmospheric Environment 12, 1991.
5. Gascoyne, M.: 1977,Atmospheric Environment 11, 395.