@article{MZ_1921__11_167651,
     author = {Ph. Frank},
     title = {Ein {Satz} \"uber ebene {Potentialstr\"omungen}},
     journal = {Mathematische Zeitschrift},
     pages = {105--107},
     publisher = {mathdoc},
     volume = {11},
     year = {1921},
     zbl = {48.0564.01},
     url = {http://geodesic.mathdoc.fr/item/MZ_1921__11_167651/}
}