@article{TDM_2002_6_a4,
     author = {G. I. Ivchenko and Yu. I. Medvedev},
     title = {Investigation of changing urn schemes parameters},
     journal = {Trudy po diskretnoj matematike},
     pages = {64--81},
     year = {2002},
     volume = {6},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/TDM_2002_6_a4/}
}