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.
Hartman M, Bolton E, Fehnel SE. Accounting for age differences on the Wisconsin Card Sorting Test: decreased working memory, not inflexibility. Psychol Aging. 2001 Sep 1;16(3):385-99.