Nola, Robert; Irzık, Gürol. 2005. Philosophy, science, education and culture. Science & technology education library. 28. Springer-Verlag. Dordrecht. str. 175. ISBN9781402037696. OCLC64310691
doi.org
Allen, Deborah E.; Donham, Richard S.; Bernhardt, Stephen A. Prosinac 2011. Problem-based learning. New Directions for Teaching and Learning. 2011 (128): 21–29. doi:10.1002/tl.465