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
Samsell B, Moore M, Bertasi G, Spinato S, Bernardello F, Rebaudi A, Sfasciotti GL, Powers R. Are bone allografts safe and effective for today's dental practitioner? Dentistry. 2014 Nov 3;4(9):1000260. doi: 10.4172/2161-1122.1000260