This paper is an extension to the recent results presented by M. Sabatini about the existence and uniqueness of limit cycles of a certain class of planar differential systems in order to include other new classes. A concrete example exhibiting the applicability of the result is introduced.
Khalil I. T. Al-Dosary. "Existence and Uniqueness of Limit Cycles in a Class of Planar Differential Systems." J. Appl. Math. 2011 1 - 7, 2011. https://doi.org/10.1155/2011/497164