Additional file 4: of Variation in population levels of physical activity in European adults according to cross-European studies: a systematic literature review within DEDIPAC LoyenAnne Van HeckeLinde VerloigneMaïtÊ HendriksenIngrid LakerveldJeroen Steene-JohannessenJostein VuilleminAnne KosterAnnemarie DonnellyAlan EkelundUlf DeforcheBenedicte De BourdeaudhuijIlse BrugJohannes van der PloegHidde 2016 Quality assessment file. (XLSX 14 kb)