@article{CMH_1981__56_139872,
     author = {Steven Hurder},
     title = {On the secondary classes of foliations with trivial normal bundles.},
     journal = {Commentarii mathematici Helvetici},
     pages = {307--326},
     publisher = {mathdoc},
     volume = {56},
     year = {1981},
     zbl = {0467.57008},
     url = {http://geodesic.mathdoc.fr/item/CMH_1981__56_139872/}
}