PV-GIS: a web-based solar radiation database for the calculation of PV potential in Europe, International Journal of Sustainable Energy, vol.8, issue.2, p.55, 2005. ,
DOI : 10.1016/S0038-092X(99)00055-9
Solar radiation climate in Africa, Solar Energy, vol.76, issue.6, p.733, 2004. ,
DOI : 10.1016/j.solener.2004.01.002