@article{IM_1985__82_143287,
     author = {R.Z. Goldstein and E.G. Turner},
     title = {Monomorphisms of finitely generated free groups have finitely generated equalizers.},
     journal = {Inventiones mathematicae},
     pages = {283--290},
     publisher = {mathdoc},
     volume = {82},
     year = {1985},
     zbl = {0582.20023},
     url = {http://geodesic.mathdoc.fr/item/IM_1985__82_143287/}
}