Kimio Oguchi Kohei Okada Shohei Terada Kunio Tojo New Optical VPN Configuration using Wavelength Routers in a WDM-Passive Optical Network. 234-239 2007 conf/icccn/2007 ICCCN http://dx.doi.org/10.1109/ICCCN.2007.4317825 db/conf/icccn/icccn2007.html#OguchiOTT07