Gameiro, M. O.; Sousa, V. O.; Gameiro, L. F.; Muchailh, R. C.; Padovani, C. R.; Amaro, J. L. Comparison of Pelvic Floor Muscle Strength Evaluations in Nulliparous and Primiparous Women: A Prospective Study . Clinics 2011, 66 (8), 1389-1394. https://doi.org/10.1590/S1807-59322011000800014.