@article{10_1090_S0894_0347_00_00342_8,
     author = {Kim, Ki and Ormes, Nicholas and Roush, Fred},
     title = {The spectra of nonnegative integer matrices via formal power series},
     journal = {Journal of the American Mathematical Society},
     pages = {773--806},
     publisher = {mathdoc},
     volume = {13},
     number = {4},
     year = {2000},
     doi = {10.1090/S0894-0347-00-00342-8},
     url = {http://geodesic.mathdoc.fr/articles/10.1090/S0894-0347-00-00342-8/}
}