Bing found these results
North American Numbering Plan - Wikipedia
List of North American Numbering Plan area codes - Wikipedia
North American Numbering Plan - Wikiwand
List of North American Numbering Plan area codes
North American Numbering Plan - Simple English Wikipedia, …
Original North American area codes - Wikipedia
Telephone numbering plan - Wikipedia
NANPA : North American Numbering Plan Administrator
NANPA : North American Numbering Plan Adminstration
NANPA : North American Numbering Plan Adminstration
- Some results have been removed