1.		Heterogeneity in urban park use a aging visitors: a latent class analysis / Astrid D. A. M. Kemperman Harry J. P. Timmermans Autor: Kemperman, Astrid D.A.M. Coautor: ; Timmermans, Harry J. P., co-autor
2.		Environmental correlates of physical activity: a review of evidence about parks and recreation / Andrew T Kaczynski, Karla A. Henderson Autor: Kaczynski, Andrew T. Coautor: ; Henderson, Karla A., co-autor