@article{ELA_2002__9__a22,
     author = {Hillar, C. and Johnson, C.R. and Spitkovsky, I.M.},
     title = {Positive eigenvalues and two-letter generalized words},
     journal = {The electronic journal of linear algebra},
     pages = {21--26},
     publisher = {mathdoc},
     volume = {9},
     year = {2002},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/ELA_2002__9__a22/}
}