@article{AM2_1981__23_136918,
     author = {Raymond Stettler},
     title = {Zur {Linearit\"at} 2-dimensionaler {Raum-Zeit-Transformationen.}},
     journal = {Aequationes mathematicae},
     pages = {266--276},
     publisher = {mathdoc},
     volume = {23},
     year = {1981},
     zbl = {0533.51003},
     url = {http://geodesic.mathdoc.fr/item/AM2_1981__23_136918/}
}