In search of a characterisation of frailty: applying exploratory factor analysis to ageing preoperative patients. - Miguel-Ruano, Guillermo; Aymerich-De-Franceschi, María; García-Aroca, Miguel Ángel; Benitez, Edgar; Pérez-Fernández, Nicolás; Álvarez-Avello, José Manuel (Perioperative Medicine, 2025)