Christensen T, Riis AH, Hatch EE, Wise LA, Nielsen MG, Rothman KJ, Toft Sorensen H, Mikkelsen EM. Costs and efficiency of online and offline recruitment methods: a web-based cohort study. J Med Internet Res. 2017 Mar 1;19(3):e58. doi: 10.2196/jmir.6716
Chandran AB, Coon CD, Martin SA, McLeod LD, Coles TM, Arnold LM. Sphygmomanometry-evoked allodynia in chronic pain patients with and without fibromyalgia. Nurs Res. 2012 Sep 1;61(5):363-8.