@article{MAN_1991__290_4_164819,
     author = {Antonella Grassi},
     title = {On minimal models of elliptic threefolds.},
     journal = {Mathematische Annalen},
     pages = {287--302},
     publisher = {mathdoc},
     volume = {290},
     number = {4},
     year = {1991},
     zbl = {0719.14006},
     url = {http://geodesic.mathdoc.fr/item/MAN_1991__290_4_164819/}
}