Takao Kawamura Ryosuke Nakatani Kazunori Sugahara P2P e-Learning System and Its Squeak-Based User Interface. 57-63 2005 conf/c5/2005 C5 http://doi.ieeecomputersociety.org/10.1109/C5.2005.22 db/conf/c5/c5-2005.html#KawamuraNS05