@article{1183506870, author = {Beckenbach, E. F.}, title = {Concerning the definition of harmonic functions}, journal = {Bull. Amer. Math. Soc.}, volume = {51}, number = {11}, year = {1945}, pages = { 240-245}, language = {en}, url = {http://dml.mathdoc.fr/item/1183506870} }
Beckenbach, E. F. Concerning the definition of harmonic functions. Bull. Amer. Math. Soc., Tome 51 (1945) no. 11, pp. 240-245. http://gdmltest.u-ga.fr/item/1183506870/