Retrieved 12 January 2014 ↑ Dialing Procedures (International Prefix, National (Trunk) Prefix and National (Significant) Number) (in Accordance with ITY-T Recommendation E.164 (11/2010)), Annex to ITU Operational Bulletin No. 994-15.XII.2011, International Telecommunication Union (ITU, Geneva), 15 December 2011. Retrieved 2 January 2014. ↑ El Salvador: A Central American Tiger?, Center for Global Liberty and Prosperity, Juan Carlos Hidalgo, 9 March 2009. ↑ "Telephone System terms and abbreviations", World Factbook, U.S. Central Intelligence Agency, 7 January 2014. Retrieved 12 January 2014.