@article{ZNSL_1994_215_a5,
     author = {A. G. Bytsko},
     title = {The zero-curvature representation for nonlinear $O(3)$ sigma-model},
     journal = {Zapiski Nauchnykh Seminarov POMI},
     pages = {100--114},
     publisher = {mathdoc},
     volume = {215},
     year = {1994},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/ZNSL_1994_215_a5/}
}