@article{1183513732, author = {Leighton, Walter}, title = {A substitute for the Picone formula}, journal = {Bull. Amer. Math. Soc.}, volume = {55}, number = {12}, year = {1949}, pages = { 325-328}, language = {en}, url = {http://dml.mathdoc.fr/item/1183513732} }
Leighton, Walter. A substitute for the Picone formula. Bull. Amer. Math. Soc., Tome 55 (1949) no. 12, pp. 325-328. http://gdmltest.u-ga.fr/item/1183513732/