@article{MZ_1968__106_171033,
     author = {Hugo Volger},
     title = {\"Uber die {Existenz} von freien {Algebren.}},
     journal = {Mathematische Zeitschrift},
     pages = {312--320},
     publisher = {mathdoc},
     volume = {106},
     year = {1968},
     zbl = {0164.01202},
     url = {http://geodesic.mathdoc.fr/item/MZ_1968__106_171033/}
}