Sustainment, Sustainability, and Spread Study (SSaSSy): protocol for a study of factors that contribute to the sustainment, sustainability, and spread of practice changes introduced through an evidence-based quality-improvement intervention in Canadian nursing homes. - Berta, Whitney B.; Wagg, Adrian; Cranley, Lisa; Doupe, Malcolm B.; Ginsburg, Liane; Hoben, Matthias; MacEachern, Lauren; Chamberlain, Stephanie; Clement, Fiona; Easterbrook, Adam; Keefe, Janice M.; Knopp-Sihota, Jennifer; et al. (Implementation Science, 2019)