4Spiro, R. J. ( 1991 ) Cognitive Flexibility, Consauctivism, and Hypertext: Random Access Instruction for Advanced Knowledge Acquisition for Ⅲ - structured Domains, In T. M. Duffy & D.H. Jonassen (Eds). Constructivism and the Technology of Instruction : A Conversation, Lawrence Erlbaum Associates, Lnc.
5H. S. Barrows & A. C. Kelson( 1995 ) : Problem - based learning in secondary education and the Problem - based learning Institute( Monographl ). Springfield IL: Problem - based learning Institute.
6Peter Schwartz, Stewart Mennin and Graham Webb. Problem- based learning: case studies, experience and practice. London: Kogan Page, 2001, 3.
7Peter Schwartz, Stewart Mennin and Graham Webb. Problem -based learning" case studies, experience and practice. London: Kogan Page, 2001, 4.
8Barbara J Duch, Susan E Groh, and Deborah E Allen. The power of problem - based learning: a practical "how to" for teaching undergraduate courses in any discipline. Sterling. Va. : Stylus Pub., 2001.6.7 40-44. 9.
9Peter Schwartz, Stewart Mennin and Graham Webb. Problem - based learning: case studies, experience and practice. London: Kogan Page, 2001, p 2.
10Schidt, H.G., Moust. J. H. C. (2000),Factors affecting small - group tutorial learning: A review of research, p28.
