R. López-Liria, P. Díaz-López, P. Rocamora-Pérez, J. M. Aguilar-Parra, A. Manzano-León, and D. Padilla-Góngora, “An active role for the elderly in the process for an integrated Europe”, JECS, vol. 7, no. 1, pp. 32–41, Jun. 2016.