@article{TMF_1998_115_3_a0,
     author = {E. Sh. Gutshabash and V. D. Lipovskii and S. S. Nikulichev},
     title = {Nonlinear $\sigma$-model in a curved space, gauge equivalence, and exact solutions of},
     journal = {Teoreti\v{c}eska\^a i matemati\v{c}eska\^a fizika},
     pages = {323--348},
     year = {1998},
     volume = {115},
     number = {3},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/TMF_1998_115_3_a0/}
}