[8]Arxivat 2017-02-28 a Wayback Machine.. Martin Kelly Thomas Jefferson Biography - Third President of the United States. Consultat el 5 de juliol de 2009
history1800s.about.com
[9]Arxivat 2015-04-07 a Wayback Machine.. Robert MacNamara. Importation of Slaves Outlawed by 1807 Act of Congress. Consultat el 5 de juliol de 2009
[7]Arxivat 2003-10-02 a Wayback Machine. Acquisition of the Public Domain 1781-1867. Consultat el 2 de setembre de 2009
[8]Arxivat 2017-02-28 a Wayback Machine.. Martin Kelly Thomas Jefferson Biography - Third President of the United States. Consultat el 5 de juliol de 2009
[9]Arxivat 2015-04-07 a Wayback Machine.. Robert MacNamara. Importation of Slaves Outlawed by 1807 Act of Congress. Consultat el 5 de juliol de 2009