Keller, C.; Paixao, A.; Moraes, M. A.; Rabelo, E. R.; Goldmeier, S. Pain Scale: Implementation for Patients in the Immediate Postoperative Period of Cardiac Surgery. Rev. Esc. Enferm. USP 2013, 47 (3), 621-625. https://doi.org/10.1590/reeusp.v47i3.78003.