Berger MS, Zhang L. New method for large quasiperiodic nonlinear oscillations with fixed frequencies for the nondissipative second type Duffing equation. TMNA [Internet]. 1995 Dec. 1 [cited 2025 Jul. 7];6(2):283-9. Available from: https://apcz.umk.pl/TMNA/article/view/TMNA.1995.046