Flokkayfirlit
Siglingafræði
Heiti Veffang Global Aviation Navigator www.globalair.com GPS World Online www.gpsworld.com GPS WWW Resource List www.averstar.com/ Institute of Navigation (ION) www.ion.org Introduction to GPS Applications www.redsword.com/gps Navigation Site, The www.web-net.nl PilotAge www.pilotage.com