@article{RCM_1989__23_1-4_181825,
     author = {Oswaldo Lezama},
     title = {Algunas observaciones acerca de matrices triangulares sobre anillos},
     journal = {Revista colombiana de matematicas},
     pages = {93--102},
     publisher = {mathdoc},
     volume = {23},
     number = {1-4},
     year = {1989},
     zbl = {0716.20032},
     url = {http://geodesic.mathdoc.fr/item/RCM_1989__23_1-4_181825/}
}