Tsunehiko Chiba Takayuki Warabino Hidetoshi Yokota Implementation and Evaluation of Handoff Method between Access Nodes for P2PSIP and IMS Cooperating Networks. 1-6 2010 ICCCN http://dx.doi.org/10.1109/ICCCN.2010.5560105 conf/icccn/2010 db/conf/icccn/icccn2010.html#ChibaWY10