Calculation of direct normal irradiation from global horizontal irradiation

1. Rodrigo, P.
2. Pérez-Higueras, P.J.
3. Almonacid, F.
4. Hontoria, L.
5. Fernández, E.F.
6. Rus, C.
7. Fernández, J.I.
8. Gómez, P.
9. Almonacid, G.