Tung Chin-chu

Publications in Math-Net.Ru

1. Positions of limit-cycles of the system $\frac{dx}{dt}=\sum_{0\le{i+k}\le2}a_{ik}x^iy^k$, $\frac{dy}{dt}=\sum_{0\le{i+k}\le2}b_{ik}x^iy^k$
   
   Matematika, 6:2 (1962),  150–168