@article{PDMA_2012_5_a47,
     author = {E. O. Karmanova},
     title = {Graph congruences: some combinatorial properties},
     journal = {Prikladnaya Diskretnaya Matematika. Supplement},
     pages = {93--94},
     publisher = {mathdoc},
     number = {5},
     year = {2012},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/PDMA_2012_5_a47/}
}