I. Belhaj, O. El Fatni, S. Barhmi, and E. H. . Saidi, “A direct normal irradiation forecasting model based on artificial neural networks”, J. Ren. Energies, vol. 19, no. 1, pp. 21 – 28, Mar. 2016, doi: 10.54966/jreen.v19i1.544.