Library of Congress. MARC Development Office. (1973). Geographic area codes (Rev.). Washington: Library of Congress.
Chicago Style CitationLibrary of Congress. MARC Development Office. Geographic Area Codes. Rev. Washington: Library of Congress, 1973.
MLA CitationLibrary of Congress. MARC Development Office. Geographic Area Codes. Rev. Washington: Library of Congress, 1973.
Warning: These citations may not always be 100% accurate.