Weierstrass Integrability of Complex Differential Equations

We characterize the complex differential equations of form $${{dy} \over {dx}} = {a_n}(x){y^n} + {a_{n - 1}}(x){y^{n 1}} \cdots {a_1}(x)y {a_0}(x),$$ where aj(x) are meromorphic functions in variable x for j 0,…,n that admit either a Weierstrass first integral or inverse integrating factor.