United States. Congress. House. Committee on Post Office and Post Roads, ProQuest (Firm), & United States. Post Office Department. (1870). Letter carrier system. Letter from the Postmaster General in answer to a resolution of the House of March 21, 1870, relative to the letter-carrier system of the United States. [publisher not identified].
Chicago Style (17th ed.) CitationUnited States. Congress. House. Committee on Post Office and Post Roads, ProQuest (Firm), and United States. Post Office Department. Letter Carrier System. Letter from the Postmaster General in Answer to a Resolution of the House of March 21, 1870, Relative to the Letter-carrier System of the United States. Washington: [publisher not identified], 1870.
MLA (9th ed.) CitationUnited States. Congress. House. Committee on Post Office and Post Roads, et al. Letter Carrier System. Letter from the Postmaster General in Answer to a Resolution of the House of March 21, 1870, Relative to the Letter-carrier System of the United States. [publisher not identified], 1870.