References
- Gallagher-Heffron, S., & Downs, R. (Eds.). (2012). Geography for life (2nd ed.). Washington, DC: National Council for Geographic Education.
- NGSS. (2014). Next Generation Science Standards. Retrieved February 1, 2015, from http://www.nextgenscience.org/sites/ngss/files/Appendix%20E%20-%20Progressions%20within%20NGSS%20-%20052213.pdf
- Pattison, W. D. (1964). The four traditions of geography. Journal of Geography, 63(3), 211–216.