Düzel, S., Voelkle, M. C., Düzel, E., Gerstorf, D., Drewelies, J., Steinhagen-Thiessen, E., et al. (2016). The Subjective Health Horizon Questionnaire (SHH-Q): Assessing the future time perspectives for facets of an active lifestyle. Gerontology, 62(3), 345-353. doi:10.1159/000441493.