@article{GDZPPN002259273, title = {On the partial differential equations of mathematical physics.}, journal = {Mathematische Annalen}, volume = {56}, year = {1903}, pages = {333-355}, zbl = {34.0827.01}, url = {http://dml.mathdoc.fr/item/GDZPPN002259273} }
Whittaker, E.T. On the partial differential equations of mathematical physics.. Mathematische Annalen, Tome 56 (1903) pp. 333-355. http://gdmltest.u-ga.fr/item/GDZPPN002259273/