Gregory Baratoff Alexander Neubeck Holger Regenbrecht Interactive Multi-Marker Calibration for Augmented Reality Applications. 107-116 2002 conf/ismar/2002 ISMAR http://csdl.computer.org/comp/proceedings/ismar/2002/1781/00/17810107abs.htm db/conf/ismar/ismar2002.html#BaratoffNR02