Jun Ota Masakazu Yamamoto Kazuo Ikeda Yasumichi Aiyama Tamio Arai Environmental Support Method for Mobile Robots Using Visual Marks with Memory Storage. 2976-2981 1999 conf/icra/1999 ICRA db/conf/icra/icra1999-4.html#OtaYIAA99 http://dx.doi.org/10.1109/ROBOT.1999.774049