G. C. Pinto-Santamaría, C. A. Ríos- Reyes, and L. Y. Vargas- Fiallo, “Use of Ecuadorian natural and acid-surfactant modified zeolites for remediation of oil- contaminated soils”, CT&F Cienc. Tecnol. Futuro, vol. 9, no. 1, pp. 93–104, May 2019.