2 citations to https://www.mathnet.ru/eng/vmumm4003

1. Yu. S. Ilyashenko, “Finiteness theorems for limit cycles: a digest of the revised proof”, Izv. Math., 80:1 (2016), 50–112                
2. Yu. S. Ilyashenko, “Finiteness theorems for limit cycles”, Russian Math. Surveys, 45:2 (1990), 129–203