@article{MAN_1982__261_182896,
     author = {Ryszard Grzaslewicz},
     title = {Extreme {Contractions} on {Real} {Hilbert} {Spaces.}},
     journal = {Mathematische Annalen},
     pages = {463--466},
     year = {1982},
     volume = {261},
     zbl = {0488.47018},
     url = {http://geodesic.mathdoc.fr/item/MAN_1982__261_182896/}
}