Li Yibo และ Sumalee Chinokul. (2012) Effects of problem-based english writing instruction on critical thinking abilities and argumentative writing skills of thai upper secondary school students. Chulalongkorn University:ม.ป.ท.Li Yibo และ Sumalee Chinokul. 2012. Effects of problem-based english writing instruction on critical thinking abilities and argumentative writing skills of thai upper secondary school students. ม.ป.ท.:Chulalongkorn University;Li Yibo และ Sumalee Chinokul. Effects of problem-based english writing instruction on critical thinking abilities and argumentative writing skills of thai upper secondary school students. ม.ป.ท.:Chulalongkorn University, 2012. Print.