@article{TM_1968_96_a10,
     author = {M. N. Yakovlev},
     title = {Nonnegative solutions of systems of nonlinear (in particular, difference) equations},
     journal = {Trudy Matematicheskogo Instituta imeni V.A. Steklova},
     pages = {111--116},
     publisher = {mathdoc},
     volume = {96},
     year = {1968},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/TM_1968_96_a10/}
}