@article{GDZPPN002077590, title = {Bericht.}, journal = {Elemente der Mathematik}, volume = {26}, year = {1971}, pages = {21-24}, url = {http://dml.mathdoc.fr/item/GDZPPN002077590} }
(éd.). Bericht.. Elemente der Mathematik, Tome 26 (1971) pp. 21-24. http://gdmltest.u-ga.fr/item/GDZPPN002077590/