Franklin JM, Dejene S, Huybrechts KF, Wang SV, Kulldorff M, Rothman KJ. A bias in the evaluation of bias comparing randomized trials with nonexperimental studies. Epidemiol Methods. 2017 Apr;6(1):20160018.. doi: 10.1515/em-2016-0018.
Cassingham KM, Sills EO, Pattanayak SK, Mansfield CA. Voluntary conservation of North Carolina's natural heritage. J For. 2002;100(5):16-23.