1. Limitations in availability of GEO operational slots: http://scholarlycommons.law.northwestern.edu/cgi/viewcontent.cgi?article=1216&context=njilb.
2. Space Track definition of GEO orbit regime: www.space-track.org.
3. Number of operational satellites in the GEO orbit: http://www.ucsusa.org/nuclear-weapons/space-weapons/satellite-database#.WRHcVojytPY.
4. “Analysis of Orbit Prediction Sensitivity to Thermal Emissions Acceleration Modeling for High Area-To-Mass Ratio (HAMR) Objects,” AMOS Technical Conference;Kelecy,2009
5. “Data Integrity in Orbital Data Fusion,” 63rd International Astronautical Congress. Naples;Vallado,2012