@article{AM2_1987__34_137230,
     author = {Andreas W.M. Dress and R. Scharlau},
     title = {Gated sets in metric spaces.},
     journal = {Aequationes mathematicae},
     pages = {112--120},
     publisher = {mathdoc},
     volume = {34},
     year = {1987},
     zbl = {0696.54022},
     url = {http://geodesic.mathdoc.fr/item/AM2_1987__34_137230/}
}