Assessing the outcomes of participatory research: protocol for identifying, selecting, appraising and synthesizing the literature for realist review oleh Greenhalgh Trish, Wong Geoff, Seller Robbyn, Bush Paula L, Sirett Erin, Henderson Jim, Salsberg Jon, Macaulay Ann C, Pluye Pierre, Jagosh Justin, Cargo Margaret, Herbert Carol P, Seifer Sarena D, Green Lawrence W