@article{RCM_1974__8_181611,
     author = {Luz G. Torres},
     title = {Una nota sobre problemas de extensi\'on},
     journal = {Revista colombiana de matematicas},
     pages = {7--14},
     publisher = {mathdoc},
     volume = {8},
     year = {1974},
     url = {http://geodesic.mathdoc.fr/item/RCM_1974__8_181611/}
}