Correcting data imbalance for semi-supervised COVID-19 detection using X-ray chest images. - Saúl Calderón Ramírez; Shengxiang Yang; Armaghan Moemeni; David A. Elizondo; Simon Colreavy-Donnelly; Luis Fernando Chavarria-Estrada; Miguel A. Molina-Cabello (Appl. Soft Comput., 2021)