2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/42891It is shown that the difference between the c-quark proton structure functions calculated in the k_T-factorization approach using different unintegrated gluon distribution functions is the same order as the difference between results obtained in the parton model and in the k_T-factorization approach.7 pages, Latex, 1 ps figures, epsf.styHigh Energy Physics - Phenomenologytext