@article{JRAM_1993__441_153547,
     author = {E. Viehweg and H\'el\`ene Esnault and B. Kahn},
     title = {Coverings with odd ramification and {Stiefel-Whitney} classes.},
     journal = {Journal f\"ur die reine und angewandte Mathematik},
     pages = {145--188},
     publisher = {mathdoc},
     volume = {441},
     year = {1993},
     zbl = {0772.57028},
     url = {http://geodesic.mathdoc.fr/item/JRAM_1993__441_153547/}
}