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
Maughan GL, Gnanasakthy A, Cooke DA. The effects of soil-applied granular pesticides on the establishment and yield of sugar-beet in commercial fields. Crop Prot. 1984 Dec;3(4):439-50.