“…second part of the Hubert's 16-th problem (which asks for the maximal possible number of limit cycles in a system x = P(x,y), y = Q(x,y) on the plane, with P and Q polynomials of degree d. See [I], [II], [13], [21], [22], [27], [28], [30], [32], [36], [37], [40], [56].…”