K. Mohd-Yusof, S. A. Helmi, M.-Z. Jamaludin, and N.-F. Harun, “Cooperative Problem-Based Learning (CPBL): A Practical PBL Model for a Typical Course”, Int. J. Emerg. Technol. Learn., vol. 6, no. 3, pp. pp. 12–20, Sep. 2011.