@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/