@article{VTGU_2018_56_a3,
     author = {D. I. Yunusova},
     title = {On the extension of pseudonorm and metrics to the semigroup ring},
     journal = {Vestnik Tomskogo gosudarstvennogo universiteta. Matematika i mehanika},
     pages = {42--56},
     publisher = {mathdoc},
     number = {56},
     year = {2018},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/VTGU_2018_56_a3/}
}