Rationale and methods of evaluation for ACHO, a new virtual assistant to improve therapeutic adherence in rural elderly populations: a user-driven living lab - Luengo-Polo, J; Conde-Caballero, D; Rivero-Jiménez, B; Ballesteros-Yáñez, I; Castillo-Sarmiento, C A; Mariano-Juárez, L (Int J Environ Res Public Health, 2021)