@article{IM_1987__88_143446,
     author = {R.M. Hain and S. Zucker},
     title = {Unipotent variations of mixed {Hodge} structure.},
     journal = {Inventiones mathematicae},
     pages = {83--124},
     publisher = {mathdoc},
     volume = {88},
     year = {1987},
     zbl = {0622.14007},
     url = {http://geodesic.mathdoc.fr/item/IM_1987__88_143446/}
}