@article{IM_1984__76_143132,
     author = {M. Boileau and H. Zieschang},
     title = {Hegaard genus of closed orientable {Seifert} 3-manifolds.},
     journal = {Inventiones mathematicae},
     pages = {455--468},
     publisher = {mathdoc},
     volume = {76},
     year = {1984},
     zbl = {0538.57004},
     url = {http://geodesic.mathdoc.fr/item/IM_1984__76_143132/}
}