@article{10_4153_CMB_1988_039_4,
     author = {Bender, E. A. and Canfield, E. R.},
     title = {The {Enumeration} of {Maps} on the {Torus} and the {Projective} {Plane}},
     journal = {Canadian mathematical bulletin},
     pages = {257--271},
     year = {1988},
     volume = {31},
     number = {3},
     doi = {10.4153/CMB-1988-039-4},
     url = {http://geodesic.mathdoc.fr/articles/10.4153/CMB-1988-039-4/}
}