@article{MZ_1983__184_173380,
     author = {Elgin H. Johnston},
     title = {On {Sets} of {Range} {Uniqueness.}},
     journal = {Mathematische Zeitschrift},
     pages = {533--548},
     year = {1983},
     volume = {184},
     zbl = {0504.30015},
     url = {http://geodesic.mathdoc.fr/item/MZ_1983__184_173380/}
}