@article{RCM_1974__8_181610,
     author = {Ives Lequin},
     title = {Differential simplicity and a criterion fornnormality},
     journal = {Revista colombiana de matematicas},
     pages = {1--6},
     year = {1974},
     volume = {8},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/RCM_1974__8_181610/}
}