International Calling Codes - Nations Online Project
Telephone numbers in Italy - Wikipedia
Telephone numbers in Poland - Wikipedia
Telephone numbers in Cyprus - Wikipedia
List of country calling codes - LCN Wiki
Telephone numbers in France - Wikipedia
North American Numbering Plan - Wikipedia
List of Michigan area codes - Wikipedia
File:List of country calling codes - Wikipedia.png - Wikipedia
Telephone numbers in Russia - Wikipedia
Telephone numbers in Iran - Wikipedia
Confluence Mobile - UN Statistics Wiki
Telephone numbers in Greece - Wikipedia
List of Illinois area codes - Wikipedia
GoTo Connect International Calling Rates
Telephone numbers in Germany - Wikipedia
List of International Calling Codes and Prefixes
List of Minnesota area codes - Wikipedia
Telephone numbers in India - Wikipedia
Area codes in the Caribbean - Wikipedia
Telephone numbers in the Netherlands - Wikipedia
Area codes 410, 443, and 667 - Wikipedia
List of dialling codes in Brazil - Wikipedia
List of dialling codes in the United Kingdom - Wikipedia
Area codes 920 and 274 - Wikipedia
Telephone numbers in Belgium - Wikipedia
