%0 Journal Article %A Kurzweil, Jaroslav %T Van der Pol perturbation of the equation for a vibrating string %J Czechoslovak Mathematical Journal %D 1967 %P 558-608 %V 17 %N 4 %I mathdoc %U http://geodesic.mathdoc.fr/articles/10.21136/CMJ.1967.100803/ %R 10.21136/CMJ.1967.100803 %G en %F 10_21136_CMJ_1967_100803