Erik Mumm Shane Farritor Paolo Pirjanian Chris Leger Paul S. Schenker Planetary Cliff Descent Using Cooperative Robots. 259-272 2004 16 Auton. Robots 3 http://dx.doi.org/10.1023/B:AURO.0000025790.37415.83 db/journals/arobots/arobots16.html#MummFPLS04