Citation: Nonaka, K., Suzuki, H., Murayama, H., Hasebe, M., Koike, T., Kobayashi, E., & Fujiwara, Y. (2017). For how many days and what types of group activities should older Japanese adults be involved in to maintain health? A 4-year longitudinal study. PLoS ONE,12(9), e0183829. Link to publisher’s article.