@article{IM_1968__5_141923,
     author = {J.P.E. HODGSON},
     title = {Obstructions to {Concordance} for {Thickenings.}},
     journal = {Inventiones mathematicae},
     pages = {292--316},
     publisher = {mathdoc},
     volume = {5},
     year = {1968},
     zbl = {0157.54304},
     url = {http://geodesic.mathdoc.fr/item/IM_1968__5_141923/}
}