Gonzalo López-Nicolás Carlos Sagüés José Jesús Guerrero Danica Kragic Patric Jensfelt 592-603 2008 56 Robotics and Autonomous Systems 7 http://dx.doi.org/10.1016/j.robot.2007.10.005 db/journals/ras/ras56.html#Lopez-NicolasSGKJ08