http://www.scribd.com/doc/2569355/Geo-Distance-Search-with-MySQL
http://earth-info.nga.mil/gns/html/namefiles.htm
https://developers.google.com/maps/documentation/javascript/services?hl=ko#Geocoding
http://www.findlatitudeandlongitude.com/?loc=Continental+Divide&id=72178
http://en.wikipedia.org/wiki/List_of_countries_by_continent_(data_file)
https://developers.google.com/maps/documentation/geocoding/?hl=ko
http://stackoverflow.com/questions/2989323/gmaps-address-component-types-get-country-name