1. DOMINO project at DBMC laboratory, UIC. http://www.cs.uic.edu/~wolfson/html/mobile.html .
2. ANSI/ISO international standard: Database language SQL. http://webstore.ansi.org .
3. Forbes online issue, April 13, 2006. http://www.forbes.com/home/digitalentertainment/2006/04/13/google-aol-yahoo -cx_rr_0417maps.html .
4. Geographic Data Technology. http://www.geographic.com .
5. Oracle 9i. http://www.oracle.com/technology/products/oracle9i .