Introduction to the study of limit cycles in planar dynamical systems
Qualitative study of linear and nonlinear ordinary differential equations
Continuous or piecewise smooth dynamical systems on 2 and 3 dimensional manifolds.
On the number of limit cycles bifurcating from a linear center
An introduction to the ordinary diferential equations qualitative theory
Local and global aspects of the qualitative theory of ordinary differential equations
On the number of limit cycles that bifurcate from a linear center