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² Tyson, Neil deGrasse. "On Being Round." http://www.haydenplanetarium.org/tyson/read/1997/03/01/on-being-round

³ "Theories for Formation of the Moon." University of Tennessee at Knoxville Department of Physics and Astronomy. http://csep10.phys.utk.edu/astr161/lect/moon/moon_formation.html

⁴ National Aeronautics and Space Administration. http://nssdc.gsfc.nasa.gov/nmc/spacecraftDisplay.do?id=1959-008A

⁵ Briggs, Lyman J. "Effect of Spin and Speed on the Lateral Deflection (Curve) of a Baseball; and the Magnus Effect for Smooth Spheres." American Journal of Physics. 27, 589--596. 1959.

⁶ "Mechanical Invention through Computation: Mechanism Basics." Massachusetts Institute of Technology Computer Science and Artificial Intelligence Laboratory. http://courses.csail.mit.edu/6.S080/lectures/02_all.pdf

⁷ "About Flywheel Energy Storage." Beacon Power. http://www.beaconpower.com/products/about-flywheels.asp

⁸ Miller, Rich. "Flywheels Gain as Alternative to Batteries." Data Center Knowledge. 26 June 2007. http://www.datacenterknowledge.com/archives/2007/06/26/flywheels-gain-as-alternative-to-batteries./