@article{1181071898, author = {Ortega, Rafael}, title = {A Forced Pendulum Equation with Many Periodic Solutions}, journal = {Rocky Mountain J. Math.}, volume = {27}, number = {4}, year = {1997}, pages = { 861-876}, language = {en}, url = {http://dml.mathdoc.fr/item/1181071898} }
Ortega, Rafael. A Forced Pendulum Equation with Many Periodic Solutions. Rocky Mountain J. Math., Tome 27 (1997) no. 4, pp. 861-876. http://gdmltest.u-ga.fr/item/1181071898/