@article{MAN_1984__269_163919,
     author = {Bruce Crauder},
     title = {Two {Reduction} {Theorems} for {Threefold} {Birational} {Morphisms.}},
     journal = {Mathematische Annalen},
     pages = {13--26},
     publisher = {mathdoc},
     volume = {269},
     year = {1984},
     zbl = {0546.14004},
     url = {http://geodesic.mathdoc.fr/item/MAN_1984__269_163919/}
}