Krisnawan KP, Arifah H. THE EFFECT OF NONLINEAR DAMPING TO A DYNAMICAL SYSTEM WITH CENTER PHASE PORTRAIT. J.Sains Dasar [Internet]. 2016 Apr. 13 [cited 2025 Jul. 4];4(1). Available from: https://jurnal.uny.ac.id/index.php/jsd/article/view/8439