Voir la notice de l'article provenant de la source European Digital Mathematics Library
@article{ELMA_1975__30_141162, author = {Otto Botsch}, title = {Die {Vierfach-Spiegelungen} an {Geraden.}}, journal = {Elemente der Mathematik}, pages = {109--111}, publisher = {mathdoc}, volume = {30}, year = {1975}, zbl = {0308.50006}, url = {http://geodesic.mathdoc.fr/item/ELMA_1975__30_141162/} }
Otto Botsch. Die Vierfach-Spiegelungen an Geraden.. Elemente der Mathematik, Tome 30 (1975), pp. 109-111. http://geodesic.mathdoc.fr/item/ELMA_1975__30_141162/