@article{PM_1993_1993_1_a5,
     author = {C\'ordoba, Antonio},
     title = {Un contraejemplo en teor{\'\i}a de operadores},
     journal = {Publicacions matem\`atiques},
     pages = {335-338},
     publisher = {mathdoc},
     volume = {37},
     number = {2},
     year = {1993},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/PM_1993_1993_1_a5/}
}