1. Locally flat embeddings of topological manifolds;Brown, Morton,1962
2. The monotone union of open 𝑛-cells is an open 𝑛-cell;Brown, Morton;Proc. Amer. Math. Soc.,1961
3. A decomposition theorem for 𝑛-dimensional manifolds;Doyle, P. H.;Proc. Amer. Math. Soc.,1962
4. H. Kneser, Geschlossen Flachen in dreidimensional Mannig-faltigkeiten, Jber. Deutsch. Math.-Verein. 38 (1929), 248-260.
5. Open manifolds with monotone union property;Kwun, Kyung Whan;Proc. Amer. Math. Soc.,1966