@article{GDZPPN002100584,
title = {Hegaard genus of closed orientable Seifert 3-manifolds.},
journal = {Inventiones mathematicae},
volume = {75},
year = {1984},
pages = {455-468},
zbl = {0538.57004},
url = {http://dml.mathdoc.fr/item/GDZPPN002100584}
}
Boileau, M.; Zieschang, H. Hegaard genus of closed orientable Seifert 3-manifolds.. Inventiones mathematicae, Tome 75 (1984) pp. 455-468. http://gdmltest.u-ga.fr/item/GDZPPN002100584/