@article{ZNSL_2013_418_a8,
     author = {G. V. Kuz'mina},
     title = {The module method and some extremal problems in the class~$\Sigma(r)$},
     journal = {Zapiski Nauchnykh Seminarov POMI},
     pages = {136--152},
     publisher = {mathdoc},
     volume = {418},
     year = {2013},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/ZNSL_2013_418_a8/}
}