@article{MZ_1962__78_170006,
     author = {Gilbert Baumslag},
     title = {On abelian hopfian groups. {I.}},
     journal = {Mathematische Zeitschrift},
     pages = {53--54},
     publisher = {mathdoc},
     volume = {78},
     year = {1962},
     zbl = {0104.02503},
     url = {http://geodesic.mathdoc.fr/item/MZ_1962__78_170006/}
}