@misc{10_1017_S0017089500007436,
     title = {Joint spectra of commuting normal operators on {Banach} spaces},
     journal = {Glasgow mathematical journal},
     pages = {339--345},
     year = {1988},
     volume = {30},
     number = {3},
     doi = {10.1017/S0017089500007436},
     url = {http://geodesic.mathdoc.fr/articles/10.1017/S0017089500007436/}
}