Kanakidou, M., N. Mihalopoulos, T. Kindap, U. Im, M. Vrekoussis, E. Gerasopoulos, E. Dermitzaki, A. Unal, M. Koçak, K. Markakis, et al.,
"Megacities as hot spots of air pollution in the East Mediterranean",
Atmospheric Environment, vol. 45, issue 6, pp. 1223-1235, 2011.
Issa, Y. M., W. F. El-Hawary, A. F. A. Youssef, and A. R. Senosy,
"Spectrophotometric Determination of Sildenafil Citrate in Pure Form and in Pharmaceutical Formulation Using Some Chromotropic Acid Azo Dyes",
Spectrochim. Acta Part A, vol. 75, issue 4, pp. 1297-1303, 210.