Maturell Aguilera A, Valiente Sandó P. Improvement of principals´ performance in comprehensive schools: it´s historical evolution in Cuba from 1899 to 2015. ASE [Internet]. 2016 Jun. 1 [cited 2024 Jul. 3];(25). Available from: https://avances.adide.org/index.php/ase/article/view/552