@article{MAN_1978__235_163151,
     author = {Eiji Horikawa},
     title = {On the {Periods} of {Enriques} {Surfaces.} {II.}},
     journal = {Mathematische Annalen},
     pages = {217--246},
     publisher = {mathdoc},
     volume = {235},
     year = {1978},
     zbl = {0412.14015},
     url = {http://geodesic.mathdoc.fr/item/MAN_1978__235_163151/}
}