1. Completely ultrametrizable spaces and continuous bijections;Brian;Top. Proc.,2015
2. General Topology;Engelking,1989
3. Summen von ℵ1 Mengen;Hausdorff;Fundam. Math.,1936
4. Trees and ultrametric spaces: a categorical equivalence;Hughes;Adv. Math.,2004
5. Classical Descriptive Set Theory;Kechris,1995