@article{GDZPPN002073315, title = {Zum Begriff des konservativen Systems.}, journal = {Elemente der Mathematik}, volume = {7}, year = {1952}, pages = {121-129}, zbl = {0048.17602}, url = {http://dml.mathdoc.fr/item/GDZPPN002073315} }
Ziegler, Hans. Zum Begriff des konservativen Systems.. Elemente der Mathematik, Tome 7 (1952) pp. 121-129. http://gdmltest.u-ga.fr/item/GDZPPN002073315/