@article{ZNSL_1990_180_a13,
     author = {G. A. Pelts},
     title = {Covariant quantization of the relativistic string with a nontrivial topology of the world sheet},
     journal = {Zapiski Nauchnykh Seminarov POMI},
     pages = {142--160},
     publisher = {mathdoc},
     volume = {180},
     year = {1990},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/ZNSL_1990_180_a13/}
}