Knowlton, D. C. (1930). The Knowlton work-book in American history. Century Co.
Lua i Stíl Chicago (17ú heag.)Knowlton, Daniel C. The Knowlton Work-book in American History. New York, London: Century Co, 1930.
Lua MLA (8ú heag.)Knowlton, Daniel C. The Knowlton Work-book in American History. Century Co, 1930.
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