Michael Wittkämper Eckhard Meier Wolfgang Broll Illuminating the Mixed Reality Stage: Applying Complex Lighting Conditions to AR. 187-188 2001 conf/ismar/2001 ISAR http://csdl.computer.org/comp/proceedings/isar/2001/1375/00/13750187abs.htm db/conf/ismar/isar2001.html#WittkamperMB01