Predictors of activity level and retention among African American lay health advisors (LHAs) from The National Witness Project: Implications for the implementation and sustainability of community-based LHA programs from a longitudinal study. - Shelton, Rachel C.; Dunston, Sheba King; Leoce, Nicole; Jandorf, Lina; Thompson, Hayley S.; Crookes, Danielle M.; Erwin, Deborah O. (Implementation Science, 2016)