1. Mathematical problems;Hilbert;(M. Newton, Transl.) Bull. Amer. Math.,1902
2. Finitely smooth normal forms of local families of diffeomorphisms and vector fields;Ilyashenko;Russian Math. Surveys,1991
3. Introduction aux Fonctions Analysables et Preuve Constructive de la Conjecture de Dulac;Écalle,1992
4. A concrete example of the existence of four limit cycles for plane quadratic systems;Shi;Sci. Sinica,1980
5. The relative position, and the number, of limit cycles of a quadratic differential system;Chen;Acta Math. Sinica,1979