@article{MAN_1988__281_4_164445,
     author = {David Gabai and William H. Kazez},
     title = {The {Classification} of {Maps} of {Nonorietable} {Surfaces.}},
     journal = {Mathematische Annalen},
     pages = {687--702},
     publisher = {mathdoc},
     volume = {281},
     number = {4},
     year = {1988},
     zbl = {0656.57001},
     url = {http://geodesic.mathdoc.fr/item/MAN_1988__281_4_164445/}
}