S. M. P. Paschoal, W. Jacob Filho, and J. Litvoc, “ Development of elderly quality of life index - EQOLI: theoretical-conceptual framework, chosen methodology, and relevant items generation ”, Clinics, vol. 62, no. 3, pp. 279–288, Jan. 2007, doi: 10.1590/S1807-59322007000300012.