@article{MZ_1955__63_169534,
     author = {G. P\'olya},
     title = {On the characteristic frequencies of a symmetric membrane.},
     journal = {Mathematische Zeitschrift},
     pages = {331--337},
     publisher = {mathdoc},
     volume = {63},
     year = {1955},
     zbl = {0065.08703},
     url = {http://geodesic.mathdoc.fr/item/MZ_1955__63_169534/}
}