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.
Lawson DH, Jick H, Rothman KJ. Coffee and tea consumption and breast disease. Surgery. 1981 Jan 1;90(5):801-3.