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
Boulanger L, Wu N, Chen SY, Nagar S, Fraser K, Bernauer MJ, Zhao Z, Zhao Y. Predictors of pain medication selection among patients diagnosed with fibromyalgia. Pain Pract. 2012 Apr;12(4):266-75.