1. Continuous k-to-1 functions between complete graphs of even order;Dugdale;Discrete Math,2008
2. J. B. Gauci A. J. W. Hilton D. Stark Wiggles and finitely discontinuous functions between graphs
3. On k-to-1 transformations;Gottschalk;Bull Amer Math Soc,1947
4. The non-existence of a certain type of continuous transformations;Harrold;Duke Math J,1939
5. There is no exactly k-to-1 function from any continuum onto [0, 1], or any dendrite, with only finitely many discontinuities;Heath;Trans Amer Math Soc,1988