@article{MM2_1974__14_154288,
     author = {Wolfgang Ruppert},
     title = {Rechtstopologische {Intervallhalbgruppen} und {Kreishalbgruppen.}},
     journal = {Manuscripta mathematica},
     pages = {183--194},
     publisher = {mathdoc},
     volume = {14},
     year = {1974},
     url = {http://geodesic.mathdoc.fr/item/MM2_1974__14_154288/}
}