@article{MAN_1905__61_158242,
     author = {Max Mason},
     title = {Beweis eines {Lemmas} der {Variationsrechnung.}},
     journal = {Mathematische Annalen},
     pages = {450--452},
     year = {1905},
     volume = {61},
     language = {de},
     url = {http://geodesic.mathdoc.fr/item/MAN_1905__61_158242/}
}