Nicolay, H. (2006). Personal Traits of Abraham Lincoln. Stackpole Books.
Lua i Stíl Chicago (17ú heag.)Nicolay, Helen. Personal Traits of Abraham Lincoln. Mechanicsb urg: Stackpole Books, 2006.
Lua MLA (9ú heag.)Nicolay, Helen. Personal Traits of Abraham Lincoln. Stackpole Books, 2006.
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