Miguel Ribo Peter Lang Harald Ganster Markus Brandner Christoph Stock Axel Pinz Hybrid Tracking for Outdoor Augmented Reality Applications. 54-63 2002 22 IEEE Computer Graphics and Applications 6 http://computer.org/cga/cg2002/g6054abs.htm db/journals/cga/cga22.html#RiboLGBSP02