Topology and its Applications
An open subset W of Sn, n ≥ 6 or n = 4, and a homotopy equivalence f : S2 × Sn-4 → W are constructed having the property that f is not homotopic to any topological embedding.
Liem, Vo Thanh; Matsumoto, Yukio; and Venema, Gerard A., "A homotopy equivalence that is not homotopic to a topological embedding" (1998). University Faculty Publications and Creative Works. 507.