Author,Title,Journal,ISSN,Publisher,Date,Volume,Number,Page,URL,URL(DOI) Sato Mai and Ishii Kaori and Shibata Ai and Mano Yoshiyuki and Oka Koichiro,Gender and grade differences in school recess physical activity among Japanese elementary school children,Japan Journal of Human Growth and Development Research,13408682,Japan Society of Human Growth and Development,2011,2011,54,54_11-54_17,https://cir.nii.ac.jp/crid/1390282680260142464,https://doi.org/10.5332/hatsuhatsu.2011.54_11