@article{MAN_1972__198_162303,
     author = {Ottmar Loos},
     title = {Alternative {Tripelsysteme.}},
     journal = {Mathematische Annalen},
     pages = {205--238},
     publisher = {mathdoc},
     volume = {198},
     year = {1972},
     zbl = {0232.17004},
     url = {http://geodesic.mathdoc.fr/item/MAN_1972__198_162303/}
}