Boyd, Anne Morris
United states government publications
H.W. Wilson, 1949
 Buku Teks SO
Walker, Edward Everett, 1900-1974
Government of the United States
Charles Scribner's Sons, 1943
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The United States of America : a government by the people
The America University, [Date of publication not identified]
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Holloway, William Vernon
State and local government in the United States
McGraw-Hill , 1951
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The United States government Internet manual
edited by Peggy Garvin
Bernan Press, 2004
 Buku Teks SO