@article{10_37236_1841,
     author = {Valery A. Liskovets},
     title = {Enumerative formulae for unrooted planar maps: a pattern},
     journal = {The electronic journal of combinatorics},
     year = {2004},
     volume = {11},
     number = {1},
     doi = {10.37236/1841},
     zbl = {1060.05046},
     url = {http://geodesic.mathdoc.fr/articles/10.37236/1841/}
}