Voir la notice de l'article provenant de la source European Digital Mathematics Library
@article{ELMA_1962__17_140750, author = {J.J. Sch\"affer}, title = {Ungel\"oste {Probleme.}}, journal = {Elemente der Mathematik}, pages = {65--65}, publisher = {mathdoc}, volume = {17}, year = {1962}, url = {http://geodesic.mathdoc.fr/item/ELMA_1962__17_140750/} }
J.J. Schäffer. Ungelöste Probleme.. Elemente der Mathematik, Tome 17 (1962), p. 65. http://geodesic.mathdoc.fr/item/ELMA_1962__17_140750/