Harlow, Ralph Volney
The United States
Holt, Rinehart and Wiston, 1961
 Buku Teks
Harlow, Ralph Volney
The United States
Holt, Rinehart and Wiston, 1961
 Buku Teks
United states
 Buku Teks
Fincher, E. B.
The President of the United States
Abelard-Schuman, 1955
 Buku Teks
Conservation in the United States
by A. F. Gustafson [and others]
Comstock Publishing Associates, 1961
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