@article{MZ_1990__203_3_174128,
     author = {Wolfgang M. Ruppert},
     title = {When is an {Abelian} {Surface} {Isomorphic} or {Isogeneous} to a {Product} of {Elliptic} {Curves?}},
     journal = {Mathematische Zeitschrift},
     pages = {293--300},
     publisher = {mathdoc},
     volume = {203},
     number = {3},
     year = {1990},
     zbl = {0712.14028},
     url = {http://geodesic.mathdoc.fr/item/MZ_1990__203_3_174128/}
}