@TECHREPORT{Ang_Est_1980,
author = "Angulo, Amparo - Salazar de Ferro, Lida - Ramirez, Maria Helena - Robayo, Olga Lucia",
title = "Estudio sobre la mineria de carbon San Vicente",
year = 1980,
institution = "Universidad Colegio Mayor De Cundinamarca",
url = "https://repositorio.unicolmayor.edu.co/handle/unicolmayor/3075",
}