@article{MAN_1977__231_163060,
     author = {A. Clausing and S. Papadopoulous},
     title = {Stable {Convex} {Sets} and {Extremal} {Operators.}},
     journal = {Mathematische Annalen},
     pages = {193--204},
     year = {1977},
     volume = {231},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/MAN_1977__231_163060/}
}