Alat hitung respons hadirin

Kaleta, Robert, and Joosten, Tanya. ""Student Response Systems: A University of Wisconsin System Study of Clickers"," Educause Center for Applied Research Research Bulletin. Vol. 2007, Issue 10, May 8, 2007, pp. 4–6. A public version of the information, in the form of a PowerPoint presentation about the findings, is available at: http://www.educause.edu/ir/library/pdf/EDU06283.pdf.