Ensemble-based bag of features for automated classification of normal and COVID-19 CXR images. - Amira S. Ashour; Merihan M. Eissa; Maram A. Wahba; Radwa A. Elsawy; Hamada Fathy Elgnainy; Mohamed Saeed Tolba; Waleed S. Mohamed (Biomed. Signal Process. Control., 2021)