3Barrows HS. A taxonomy of problem-based learning methods. Med Edu, 1986, ( 20 ) :481-486.
4Dochy F, Segers M, Bossche PV, et al. Effects of problem-based learn- ing : a meta-analysis. Learning and Instruction ,2003,13 ( 5 ) :533-568.
5Tannizia RA,Tarmizib MAA, Loginina NI,et al. Problem-based learn- ing:engaging students in acquisition of mathematical competency. Proce- dia Social and Behavioral Sciences, 2010 ( 2 ) :4683-4688.