L. A. de Moura, A. C. D. de Oliveira, G. de A. Pereira, and L. V. Pereira, “Postoperative pain in children: a gender approach”, Rev. Esc. Enferm. USP, vol. 45, no. 4, pp. 833–838, Aug. 2011, doi: 10.1590/S0080-62342011000400006.