9Hmelo,C. E. ,& Ferrari,M. (1997). The Problem-base leaning tutorial: Cultivation higher order thinking skills [J].Journal for the Education of the Gifted. Vol. 20(4) ,pp401-422.
10Barrows,H. S. ,& Kelson,A, C. (1995). Problem-based learning in secondary education and the Problem-Based Lerning Institute (Monograph 1 ) [J]. Springfield IL : Problem - Based Learning Institute.