http://www.inquisitr.com/1858141/guardbot-u-s-marines-field-testing-cute-spherical-robot-that-can-swim-and-roll-on-any-terrain-video/

http://www.nydailynews.com/news/national/marines-test-guardbot-amphibious-robotic-ball-article-1.2121581


http://www.ibtimes.co.uk/guardbot-us-marines-testing-robot-guard-balls-that-can-swim-roll-any-terrain-1488489