EXTRICATING JUSTIFICATION SCHEME THEORY IN MIDDLE SCHOOL MATHEMATICAL PROBLEM SOLVING.Published in:Investigations in Mathematics Learning, 2012, v. 5, n. 1, p. 38, doi. 10.1080/24727466.2012.11790319By:Mattesoo, Shirley;Capraro, Mary Margaret;Capraro, Robert M.;Lincoln, Yvonma S.Publication type:Article