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Falsehoods Programmers Believe About Phone Numbers
Google's common Java, C++ and JavaScript library for parsing, formatting, and validating international phone numbers. - google/libphonenumber
2016), phones in the disputed territory and partially recognised state of Kosovo may be reached by dialing the country calling code for Serbia (+381), Slovenia (+386), or Monaco (+377), depending on where and when one obtained the number. The country or area code of a phone number indicates the user's location, place of residence, time-zone, or preferred language Unless a piece of user-supplied data has actually been verified to be a phone number, it should be stored as-is as entered by the user.
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