References:

Ertmer, P., & Simons, K. (2006). Jumping the PBL implementation hurdle: Supporting the efforts of K–12 teachers. The Interdisciplinary Journal of Problem-Based Learning, 1(1), 40–54. Retrieved from http://docs.lib.purdue.edu/cgi/viewcontent.cgi?article=1005&context=ijpbl

Laureate Education, Inc. (Executive Producer). (2009). Integrating technology across the content areas. Baltimore, MD: Author.