- "Global Positioning System Overview" . http://www.colorado.edu/geography/gcraft/notes/gps/gps_f.html. (Mayo 14, 2003).
- "Global Positioning System". http://encarta.msn.com/encnet/refpages/RefArticle.aspx?refid=761579727 . (Mayo 12, 2003)
- "New GPS tracking service". Proquest. Computimes Malaysia. New York Aug 23, 2001. (Mayo 13, 2003).
- Vehicle location system streamlines outage management". Proquest. Electrical World. New York October 1997. (Mayo 13, 2003).
- "Tracking company vehicles made easier with positioning-location system". Proquest. Air Conditioning, Heating & Refrigeration. News Troy Dec 21, 1998. (Mayo 12, 2003).
- http://www.syscom.com.mx
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