Pawitan, Jeanne A., and Dewi Sukmawati. “Association Between Presence in Lectures and Student Knowledge Gain in Problem Based Learning: Experience in Neuropsychiatry Module, FMUI, International Program”. Medical Journal of Indonesia 18, no. 2 (May 1, 2009): 131-4. Accessed September 27, 2020. http://mji.ui.ac.id/journal/index.php/mji/article/view/353.