@article{EXMATH_2006_2006_1_a16,
     author = {Bel Hadj Fredj, Olfa},
     title = {Espectro de decremento esencial y perturbaciones compactas que conmutan.},
     journal = {Extracta mathematicae},
     pages = {261-271},
     publisher = {mathdoc},
     volume = {21},
     number = {3},
     year = {2006},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/EXMATH_2006_2006_1_a16/}
}