Establishing best practices in cancer online support groups: protocol for a realist review oleh Geoff Wong, Holly Witteman, Henry Potts, Andrea C Tricco, Olga Perski, Marina Englesakis, Jacqueline L Bender, Charlene Soobiah, Mary Jane Esplen, Richard Wassersug, Stephanie Babinski, Alaina B Cyr, Colleen Young, Victoria Forster, Janet Papadakos, Colleen Fox, Alison Gothard-Huang