DiTrapani J, Rockwood N, Jeon M. Explanatory IRT analysis using the SPIRT macro in SPSS. TQMP. 2018;14(2):81-98. doi: 10.20982/tqmp.14.2.p081
Brubaker L, Richter HE, Barber MD, Hsu Y, Rahn DD, Menefee S, Visco A, Spino C, Martin S, Meikle SF. Pelvic floor disorders clinical trials: participant recruitment and retention. Int Urogynecol J. 2013 Jan 1;24(1):73-9.