Hiroyuki Tarumi Keitaro Yamada Takafumi Daikoku Fusako Kusunoki Shigenori Inagaki Makiko Takenaka Design and evaluation of a virtual mobile time machine in education. 334-337 2008 Advances in Computer Entertainment Technology http://doi.acm.org/10.1145/1501750.1501829 conf/ACMace/2008 db/conf/ACMace/ace2008.html#TarumiYDKIT08