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
Lock EF, Ziemiecki RM, Marron J, Dittmer DP. Efficiency clustering for low-density microarrays and its application to QPCR. BMC Bioinformatics. 2010 Jul;11(386).