@article{ZNSL_1991_191_a12,
     author = {A. I. Skopin},
     title = {The graphic construction of collecting formula for some types of groups},
     journal = {Zapiski Nauchnykh Seminarov POMI},
     pages = {140--151},
     publisher = {mathdoc},
     volume = {191},
     year = {1991},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/ZNSL_1991_191_a12/}
}