@article{10_1017_S0017089500035758,
     author = {Plafker, Stephen},
     title = {The spectral theorem in {Banach} algebras},
     journal = {Glasgow mathematical journal},
     pages = {49--55},
     year = {1972},
     volume = {13},
     number = {1},
     doi = {10.1017/S0017089500035758},
     url = {http://geodesic.mathdoc.fr/articles/10.1017/S0017089500035758/}
}