1. Topological Groups and Related Structures;Arhangel'skii,2008
2. On the metric structure of hyperspaces with Hausdorff metric;Bandt;Math. Nachr.,1986
3. Partitioning a set;Bing;Bull. Am. Math. Soc.,1949
4. On symmetric products of topological spaces;Borsuk;Bull. Am. Math. Soc.,1931
5. The third symmetric product of R;Borovikova;Comput. Methods Funct. Theory,2009