Ilyashenko Y., “Selected topics in differential equations with real and complex time”, Normal Forms, Bifurcations and Finiteness Problems in Differential Equations, Nato Science Series, Series II: Mathematics, Physics and Chemistry, 137, 2004, 317–354
Yulij Ilyashenko, Normal Forms, Bifurcations and Finiteness Problems in Differential Equations, 2004, 317
Ilyashenko, Y, “Centennial history of Hilbert's 16th problem”, Bulletin of the American Mathematical Society, 39:3 (2002), 301