VILLAMIL, T. “Depositional and Geochemical Cyclicity in the Cretaceous Fine-Grained Strata of Colombia. A Model for Organic Matter Content”. CT&F - Ciencia, Tecnología y Futuro 1, no. 2 (December 31, 1996): 5–23. Accessed May 4, 2024. https://ctyf.journal.ecopetrol.com.co/index.php/ctyf/article/view/594.