@article{ZNSL_1981_111_a4,
     author = {V. V. Ishkhanov},
     title = {Positivity of the principal minors of a nonsingular $M$-matrix},
     journal = {Zapiski Nauchnykh Seminarov POMI},
     pages = {88},
     publisher = {mathdoc},
     volume = {111},
     year = {1981},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/ZNSL_1981_111_a4/}
}