[[1] Grzegorz Bancerek. Cardinal numbers. Formalized Mathematics, 1(2):377-382, 1990.]Search in Google Scholar
[[2] Grzegorz Bancerek. On constructing topological spaces and Sorgenfrey line. Formalized Mathematics, 13(1):171-179, 2005.]Search in Google Scholar
[[3] Grzegorz Bancerek. Niemytzki plane - an example of Tychonoff space which is not T4. Formalized Mathematics, 13(4):515-524, 2005.]Search in Google Scholar
[[4] Grzegorz Bancerek. Bases and refinements of topologies. Formalized Mathematics, 7(1): 35-43, 1998.]Search in Google Scholar
[[5] Czesław Bylinski. Functions from a set to a set. Formalized Mathematics, 1(1):153-164, 1990.]Search in Google Scholar
[[6] Czesław Bylinski. Some basic properties of sets. Formalized Mathematics, 1(1):47-53, 1990.]Search in Google Scholar
[[7] Agata Darmochwał and Yatsuka Nakamura. Metric spaces as topological spaces - fundamental concepts. Formalized Mathematics, 2(4):605-608, 1991.]Search in Google Scholar
[[8] Ryszard Engelking. Outline of General Topology. North-Holland Publishing Company, 1968.]Search in Google Scholar
[[9] Adam Grabowski. On the boundary and derivative of a set. Formalized Mathematics, 13 (1):139-146, 2005.]Search in Google Scholar
[[10] Adam Grabowski. On the Borel families of subsets of topological spaces. Formalized Mathematics, 13(4):453-461, 2005.]Search in Google Scholar
[[11] Andrzej Kondracki. Basic properties of rational numbers. Formalized Mathematics, 1(5): 841-845, 1990.]Search in Google Scholar
[[12] Beata Padlewska and Agata Darmochwał. Topological spaces and continuous functions. Formalized Mathematics, 1(1):223-230, 1990.]Search in Google Scholar
[[13] Karol Pak. Basic properties of metrizable topological spaces. Formalized Mathematics, 17(3):201-205, 2009. doi:10.2478/v10037-009-0024-8.10.2478/v10037-009-0024-8]Search in Google Scholar
[[14] Konrad Raczkowski and Paweł Sadowski. Topological properties of subsets in real numbers. Formalized Mathematics, 1(4):777-780, 1990.]Search in Google Scholar
[[15] Lynn Arthur Steen and J. Arthur Jr. Seebach. Counterexamples in Topology. Springer- Verlag, 1978.]Search in Google Scholar
[[16] Andrzej Trybulec. A Borsuk theorem on homotopy types. Formalized Mathematics, 2(4): 535-545, 1991.]Search in Google Scholar
[[17] Andrzej Trybulec. Subsets of complex numbers. Mizar Mathematical Library.]Search in Google Scholar
[[18] Zinaida Trybulec. Properties of subsets. Formalized Mathematics, 1(1):67-71, 1990.]Search in Google Scholar
[[19] Edmund Woronowicz. Relations and their basic properties. Formalized Mathematics, 1 (1):73-83, 1990.]Search in Google Scholar
[[20] Mirosław Wysocki and Agata Darmochwał. Subsets of topological spaces. Formalized Mathematics, 1(1):231-237, 1990.]Search in Google Scholar