Mansfield C, Tangka FKL, Ekwueme DU, Smith JL, Guy GP, Li C, Hauber AB. Stated preference for cancer screening: a systematic review of the literature, 1990–2013. Prev Chronic Dis. 2016 Feb 25;13:E27. doi: 10.5888/pcd13.150433
Pattanayak SK, Poulos C, Yang JC, Patil SR, Wendland KJ. Of taps and toilets: quasi-experimental protocol for evaluating community-demand-driven projects. J Water Health. 2009 Sep 1;7(3):434-51.