Bolívar-León, Rafael, Neyl Richard Triviño-Jaimes, and Javier Mauricio García-Mogollón. 2014. “A Technical and Environmental Study of Fortified Structures Used in Coal Mining in Norte De Santander”. Revista Facultad De Ingeniería 24 (38):107-16. https://doi.org/10.19053/01211129.3162.