1. On the effect of ordinary light on small ion concentration;ElNadi;Math. and Phys. Soc. of Egypt No.,1958
2. The intermediate ions in the atmosphere;Hogg;Proc. Phys. Soc.,1939
3. Israel, H. , Fries, G. and Dolezalek, H. , 1956: Technical Note No. 7. Contract No. AF 61 (514) 640. Air Research and Development Command U.S. Air Force..
4. Intermediate and large atmospheric ions at Cairo-Giza;Ortner;J. Atmosph. Terr. Phys.,1955
5. Condensation nuclei. Symposium in Dublin;Pollak;Nature,1955