Meseck, K., M. Jankowska, J. Schipperijn, L. Natarajan, S. Godbole, J. Carlson, M. Takemoto, K. Crist, and J. Kerr. “Is Missing Geographic Positioning System Data in Accelerometry Studies a Problem, and Is Imputation the Solution?”. Geospatial Health, Vol. 11, no. 2, May 2016, doi:10.4081/gh.2016.403.