Dewulf, Bart, Tijs Neutens, Delfien Van Dyck, Ilse De Bourdeaudhuij, Steven Broekx, Carolien Beckx, and Nico Van de Weghe. 2016. “Associations Between Time Spent in Green Areas and Physical Activity Among Late Middle-Aged Adults”. Geospatial Health 11 (3). https://doi.org/10.4081/gh.2016.411.