@article {181580,
	title = {including aerosol optical depth improves existing models for the retrieval in cloud-free conditions of the direct normal from the measured global irradiance in Egypt},
	journal = {Meteorologische Zeitschrift},
	year = {2017},
	author = {Boraiy, M. and Korany, M and Aoun, Y. and S.C. Alfaro and M. El-Metwally and M.M. Abdel Wahab and Blanc, P. and Eissa, Y. and H. Ghedira and G. Siour and K. Hungershoefer and Wald, L.}
}
