Prime Archives in PhysicsPhase Portraits of the Autonomous Duffing Single-Degree-of-Freedom Oscillator with Coulomb Dry FrictionDOI: 10.37247/PAP.1.2020.2ADownloadPhase-Portraits-of-the-Autonomous-Duffing-Single-Degree-of-Freedom-Oscillator-with-Coulomb-Dry-Friction