@article{10_4153_CJM_1980_060_2,
     author = {Penna, Michael A.},
     title = {Euler {Classes} of {Combinatorial} {Manifolds}},
     journal = {Canadian journal of mathematics},
     pages = {783--803},
     year = {1980},
     volume = {32},
     number = {4},
     doi = {10.4153/CJM-1980-060-2},
     url = {http://geodesic.mathdoc.fr/articles/10.4153/CJM-1980-060-2/}
}