Clear-sky models evaluation of two sites over Algeria for PV forecasting purpose Kacem Gairaa, Saïd Benkaciali and Mawloud Guermoui Eur. Phys. J. Plus, 134 10 (2019) 534 Published online: 25 October 2019 DOI: 10.1140/epjp/i2019-12917-2