@article{IM_1968__6_141933,
     author = {V.J. LAL},
     title = {Wall {Obstruction} of a {Fibration.}},
     journal = {Inventiones mathematicae},
     pages = {67--77},
     publisher = {mathdoc},
     volume = {6},
     year = {1968},
     zbl = {0159.53602},
     url = {http://geodesic.mathdoc.fr/item/IM_1968__6_141933/}
}