@article{1183530934, author = {Coffman, C. V. and Wong, J. S. W.}, title = {Second order nonlinear oscillations}, journal = {Bull. Amer. Math. Soc.}, volume = {75}, number = {5}, year = {1969}, pages = { 1379-1382}, language = {en}, url = {http://dml.mathdoc.fr/item/1183530934} }
Coffman, C. V.; Wong, J. S. W. Second order nonlinear oscillations. Bull. Amer. Math. Soc., Tome 75 (1969) no. 5, pp. 1379-1382. http://gdmltest.u-ga.fr/item/1183530934/