@article{TMF_1986_67_1_a5,
     author = {V. K. Krivoshchekov and P. B. Medvedev},
     title = {Minimal $R$~operation in the $1/N$~expansion of $\sigma$~models},
     journal = {Teoreti\v{c}eska\^a i matemati\v{c}eska\^a fizika},
     pages = {52--67},
     publisher = {mathdoc},
     volume = {67},
     number = {1},
     year = {1986},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/TMF_1986_67_1_a5/}
}