@article{EXMATH_1986_1986_1_a26,
     author = {Weis, Lutz W.},
     title = {Sobre el espectro de orden esencial},
     journal = {Extracta mathematicae},
     pages = {88-90},
     publisher = {mathdoc},
     volume = {1},
     number = {2},
     year = {1986},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/EXMATH_1986_1986_1_a26/}
}