@article{MS2_1955__3_165596,
     author = {G.E.H. REUTER},
     title = {A note on contraction semigroups},
     journal = {Mathematica Scandinavica},
     pages = {275--280},
     publisher = {mathdoc},
     volume = {3},
     year = {1955},
     zbl = {0067.35301},
     url = {http://geodesic.mathdoc.fr/item/MS2_1955__3_165596/}
}