1. (2012) Gas and liquid transmission pipelines. Thompson
2. http://www.nrec.ri.cmu.edu/projects/explorer/description/
3. www.robaid.com/bionics/tbcp-ii-robot-uses-gecko-tape-coated-belts-to-climb-smooth-surfaces.htm
4. http://spectrum.ieee.org/automaton/robotics/robotics-hardware/speedy-inchworm-robot-only-needs-one-motor
5. http://www.puretechltd.com/products/smartball/smartball_leak_detection.shtml