Sufficient conditions for the univalence of quasiconformal mappings

Using two methods, quasiconformal continuation involving a theorem of Hadamard and direct estimation of $f(z_2)-f(z_1)$, we obtain sufficient conditions for the univalence of continuously differentiable mappings $f(z)$ of plane domains which, in the case of conformal mappings, reduce to both well-known and new results.