Macnaughton E, Stefancic A, Nelson G, Caplan R, Townley G, Aubry T, McCullough S, Patterson M, Stergiopoulos V, Vallée C, Tsemberis S, Fleury M-J, Piat M, Goering P. Implementing Housing First Across Sites and Over Time: Later Fidelity and Implementation Evaluation of a Pan-Canadian Multi-site Housing First Program for Homeless People with Mental Illness. Am J Community Psychol. 2015;55(3-4):279-91.