@article{MAN_1991__289_4_164791,
     author = {C. Bidard and M. Zerner},
     title = {The {Perron-Frobenius} theorem in relative spectral theory.},
     journal = {Mathematische Annalen},
     pages = {451--464},
     publisher = {mathdoc},
     volume = {289},
     number = {4},
     year = {1991},
     zbl = {0712.47032},
     url = {http://geodesic.mathdoc.fr/item/MAN_1991__289_4_164791/}
}