@article{MAN_1985__271_163987,
     author = {Francois R. Cossec},
     title = {On the {Picard} {Group} of {Enriques} {Surfaces.}},
     journal = {Mathematische Annalen},
     pages = {577--600},
     publisher = {mathdoc},
     volume = {271},
     year = {1985},
     zbl = {0541.14031},
     url = {http://geodesic.mathdoc.fr/item/MAN_1985__271_163987/}
}