@article{GMJ_2001__8_1_49178,
     author = {Ronto, A.N. and Ront\'o, M. and Samoilenko, A.M. and Trofimchuk, S.I.},
     title = {On periodic solutions of autonomous difference equations.},
     journal = {Georgian Mathematical Journal},
     pages = {135--164},
     publisher = {mathdoc},
     volume = {8},
     number = {1},
     year = {2001},
     zbl = {0985.39010},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/GMJ_2001__8_1_49178/}
}