@article{TMF_1999_121_2_a1,
     author = {A. M. Semikhatov and B. L. Feigin},
     title = {Free-field resolutions of unitary representations of the $N=2$ {Virasoro} algebra: {II.~The} butterfly resolution},
     journal = {Teoreti\v{c}eska\^a i matemati\v{c}eska\^a fizika},
     pages = {244--257},
     publisher = {mathdoc},
     volume = {121},
     number = {2},
     year = {1999},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/TMF_1999_121_2_a1/}
}