1. On a class of continuous mappings;Borsuk, Karol;Fund. Math.,1957
2. Two-to-one mappings of manifolds;Civin, Paul;Duke Math. J.,1943
3. 𝑛-to-one mappings of linear graphs;Gilbert, Paul W.;Duke Math. J.,1942
4. On 𝑘-to-1 transformations;Gottschalk, W. H.;Bull. Amer. Math. Soc.,1947
5. The non-existence of a certain type of continuous transformation;Harrold, O. G., Jr.;Duke Math. J.,1939