Harold W. Kuhn. Some Combinatorial Lemmas in Topology. IBM Journal of Research and Development, 4(5):518-524, 1960. [doi]
@article{Kuhn60, title = {Some Combinatorial Lemmas in Topology}, author = {Harold W. Kuhn}, year = {1960}, doi = {10.1147/rd.45.0518}, url = {http://dx.doi.org/10.1147/rd.45.0518}, researchr = {https://researchr.org/publication/Kuhn60}, cites = {0}, citedby = {0}, journal = {IBM Journal of Research and Development}, volume = {4}, number = {5}, pages = {518-524}, }