Marquéz, N., G. Litwinski, and L. Rogers. “Fractionation and Characterization of Demetallated Non-Porphyrins from Boscan Crude Oil”. Rev. Téc. Fac. Ing. Univ. Zulia, Vol. 13, no. 2, 1, https://produccioncientifica.luz.edu.ve/index.php/tecnica/article/view/5362.