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
Jimenez-Murcia S, Granero R, Fernandez-Aranda F, Arcelus J, Aymami MN, Gomez-Pena M, Tarrega S, Moragas L, del Pino-Gutierrez A, Sauchelli S, Fagundo AB, Brewin N, Menchon JM. Predictors of outcome among pathological gamblers receiving cognitive behavioral group therapy. Eur Addict Res. 2015;21(4):169-78. doi: 10.1159/000369528