McGee, Ben Wright. “The Implications Of Relativistic Time Dilation On The Nature Of Physical Time: A Non-Newtonian Interpretation Of Special Relativity.”  Kronoscope 6.2 (2006): 175-191.

Nave, C.R. "Gravitational Red Shift." General Relativity.  Georgia State University, 2014. Web.  22 Nov. 2014

Pogge, Richard. "GPS and Relativity."  GPS and Relativity.  N.P. 10 Apr. 2014.  Web.  22 Nov. 2014

Riebeek, Holli. "Catalog of Earth Satellite Orbits: Feature Articles."  Catalog of Earth Satellite Orbits: Feature Articles.  NASA, 4 Sept. 2009.  Web.  22 Nov. 2014