@article{JRAM_1991__422_153371,
     author = {J. Agler and E. Franks and D.A. Herrero},
     title = {Spectral pictures of operators quasisimilar to the unilateral shift.},
     journal = {Journal f\"ur die reine und angewandte Mathematik},
     pages = {1--20},
     publisher = {mathdoc},
     volume = {422},
     year = {1991},
     zbl = {0777.47015},
     url = {http://geodesic.mathdoc.fr/item/JRAM_1991__422_153371/}
}