The theorem was also proven earlier (but not published) by Pontryagin in 1927-1928, and six months later than Kuratowski by Frink and Smith (Kullman 1979; Harary 1981;
Harris et al. 2000, p. 43). Kennedy et al. (1985) give a detailed
history of the theorem.
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"Kuratowski's Theorem." In Graph
Theory. Reading, MA: Addison-Wesley, pp. 108-113, 1994.Harary,
F. "Homage to the Memory of Kazimierz Kuratowski." J. Graph Th.5,
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Combinatorics
and Graph Theory. New York: Springer, 2000.Kennedy, J. W.;
Quintas, L. V.; and Syslo, M. M. "The Theorem on Planar Graphs."
Historia Math.12, 356-368, 1985.Kullman, D. E. "The
Utilities Problem." Math. Mag.52, 299-302, 1979.Kuratowski,
C. "Sur l'operation A de l'analysis situs." Fund. Math.3,
182-199, 1922.Kuratowski, C. "Sur le problème des courbes
gauches en topologie." Fund. Math.15, 217-283, 1930.Skiena,
S. Implementing
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Theorem." J. Graph Th.5, 225-241, 1981.Thomassen,
C. "A Link Between the Jordan Curve Theorem and the Kuratowski Planarity Criterion."
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Introduction
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2000.
(i.e., the complete bipartite graph on
two sets of three vertices) or the pentatope graph 
as a homeomorphic subgraph. These
graphs are sometimes known as Kuratowski graphs.
