@article{ŞUBĂ_TURUTA_2019, title={CUBIC DIFFERENTIAL SYSTEMS WITH A WEAK FOCUS AND A REAL INVARIANT STRAIGHT LINE OF MAXIMAL ALGEBRAIC MULTIPLICITY }, volume={4}, url={https://revista.ust.md/index.php/acta_exacte/article/view/359}, DOI={10.36120/2587-3644.v4i2.119-130}, abstractNote={<p>In this article, we show that in the set of all cubic systems of differential equations with a weak focus the maximal algebraic multiplicity of an invariant affine and real straight line is four. There are three classes of these systems. For each of these classes the problem of center is solved.</p>}, number={2}, journal={Acta et Commentationes Exact and Natural Sciences}, author={ŞUBĂ, Alexandru and TURUTA, Silvia}, year={2019}, month={Jul.}, pages={119-130} }