@article{MAN_1991__290_4_164845,
     author = {Herbert Lange and Christina Birkenhake},
     title = {The exponent of an abelian subvariety.},
     journal = {Mathematische Annalen},
     pages = {801--814},
     publisher = {mathdoc},
     volume = {290},
     number = {4},
     year = {1991},
     zbl = {0773.14024},
     url = {http://geodesic.mathdoc.fr/item/MAN_1991__290_4_164845/}
}