Velásquez Henao, J. D., Y. Olaya Morales, and C. J. Franco Cadena. “Evidence of Structural Changes in the Average Monthly Price of West Texas Intermediate (WTI) Oil”. Cuadernos De Administración, vol. 22, no. 38, June 2009, https://revistas.javeriana.edu.co/index.php/cuadernos_admon/article/view/3873.