@article{AM2_1992__44_1_137483,
     author = {J.-M. Belley and G. Fournier},
     title = {Almost periodic weak solutions to forced pendulum type equations without friction.},
     journal = {Aequationes mathematicae},
     pages = {100--108},
     publisher = {mathdoc},
     volume = {44},
     number = {1},
     year = {1992},
     zbl = {0763.34035},
     url = {http://geodesic.mathdoc.fr/item/AM2_1992__44_1_137483/}
}