T. R. Blows

Bifurcation of Limit Cycles from Centers and Separatrix Cycles of Planar Analytic Systems

T. R. Blows, Lawrence M. Perko, L. Perko, 1994, SIAM Rev..

The number of limit cycles of certain polynomial differential equations

T. R. Blows, N. G. Lloyd, N. Lloyd, 1984, Proceedings of the Royal Society of Edinburgh: Section A Mathematics.