Morton Brown, Locally flat embeddings of topological manifolds in Topology of 3–manifolds and related topics (Proceedings of the University of Georgia Institute, 1961),pp. 83 – 91. Prentice – Hall, Englewood Cliffs, N.J., 1962
Morton Brown, Locally flat imbeddings of topological manifolds, Annals of Mathematics, Vol. 75 (1962), p. 331-341 (jstor:1970177)
(on the collar neighbourhood theorem)