@article{EXMATH_2003_2003_1_a24,
     author = {Ech-Cherif El Kettani, Mustapha and El Bouchibti, El Houcine},
     title = {Sobre las transformaciones aditivas que conservan el espectro de sobreyecci\'on.},
     journal = {Extracta mathematicae},
     pages = {57-64},
     year = {2003},
     volume = {18},
     number = {1},
     language = {fr},
     url = {http://geodesic.mathdoc.fr/item/EXMATH_2003_2003_1_a24/}
}