@article{VMP_2015_16_2_a4,
     author = {M. A. Nokel and N. V. Lukashevich},
     title = {Topic models: adding bigrams and taking account of the similarity between unigrams and bigrams},
     journal = {Numerical methods and programming},
     pages = {215--234},
     publisher = {mathdoc},
     volume = {16},
     number = {2},
     year = {2015},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/VMP_2015_16_2_a4/}
}