@article{IM_1973__21_142229,
     author = {Allen E. Hatcher},
     title = {Cocordance and {Isotopy} of {Smooth} {Embeddings} in {Low} {Codimensions.}},
     journal = {Inventiones mathematicae},
     pages = {223--232},
     publisher = {mathdoc},
     volume = {21},
     year = {1973},
     zbl = {0254.57017},
     url = {http://geodesic.mathdoc.fr/item/IM_1973__21_142229/}
}