@article{PORMA_1952__11_1_114695,
     author = {Bott, Raoul},
     title = {Two new combinatorial invariants for polyhedra},
     journal = {Portugaliae mathematica},
     pages = {35--40},
     publisher = {mathdoc},
     volume = {11},
     number = {1},
     year = {1952},
     mrnumber = {0048820},
     zbl = {0047.42003},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/PORMA_1952__11_1_114695/}
}