Limit Cycles of Continuous Piecewise Differential Systems Formed by Linear and Quadratic Isochronous Centers I. - Bilal Ghermoul; Jaume Llibre; Tayeb Salhi (Int. J. Bifurc. Chaos, 2022)

Limit Cycles of Piecewise-Continuous Differential Systems Formed by Linear and Quadratic Isochronous Centers II. - Bilal Ghermoul; Jaume Llibre; Tayeb Salhi (Int. J. Bifurc. Chaos, 2022)