Obarzanek E, Vollmer WM, Lin PH, Cooper LS, Young DR, Ard JD, Stevens VJ, Simons-Morton DG, Svetkey LP, Harsha DW, Elmer PJ, Appel LJ. Effects of individual components of multiple behavior changes: the PREMIER trial. Am J Health Behav. 2007 Sep-Oct; 31(5):545-60.