http://pbln.imsa.edu/model/template/
http://www.udel.edu/inst/
http://www.pbli.org/pbl/generic_pbl.htm
http://www.maastrichtuniversity.nl/web/Main/Education/EducationalProfile/ProblemBasedLearning.htm
http://www.lycos.com/info/problem-based-learning.html
http://www.kem.edu/dept/METC/PBL%20Ramnarayan.pdf
http://www.bhmed-emanual.org/book/export/html/1
http://cte.umdnj.edu/active_learning/active_pbl.cfm
http://www2.glos.ac.uk/offload/ceal/resources/qualities.pdf
http://www.studygs.net/pbl.htm
http://bjmp.org/files/2010-3-2/bjmp-2010-3-2-313.pdf
http://www.ibl.liu.se/vufo/mad/filarkiv/1.76923/pblteachers.pdf
http://www.rsmas.miami.edu/groups/niehs/ambient/teacher/Tpbl.html
http://fhs.mcmaster.ca/facdev/documents/tutorPBL.pdf
http://www.mcli.dist.maricopa.edu/pbl/ubuytutor/role.html
http://www.biomedcentral.com/content/pdf/1472-6920-5-20.pdf