@article{PM_1988_1988_1_a15,
     author = {Gonz\'alez, Manuel},
     title = {Especies nulas y rangos de polinomios de operadores.},
     journal = {Publicacions matem\`atiques},
     pages = {167-170},
     publisher = {mathdoc},
     volume = {32},
     number = {2},
     year = {1988},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/PM_1988_1988_1_a15/}
}