@article{1183420248, author = {Underhill, A. L.}, title = {The second variation of a definite integral}, journal = {Bull. Amer. Math. Soc.}, volume = {16}, number = {3}, year = {1909}, pages = { 379-384}, language = {en}, url = {http://dml.mathdoc.fr/item/1183420248} }
Underhill, A. L. The second variation of a definite integral. Bull. Amer. Math. Soc., Tome 16 (1909) no. 3, pp. 379-384. http://gdmltest.u-ga.fr/item/1183420248/