@article{IM_1987__90_143521,
     author = {S. Morita},
     title = {Characteristic classes of surface bundles.},
     journal = {Inventiones mathematicae},
     pages = {551--578},
     year = {1987},
     volume = {90},
     zbl = {0608.57020},
     url = {http://geodesic.mathdoc.fr/item/IM_1987__90_143521/}
}