^Petersen, William; Novak, Michael; Gleason, Philip (1982). Concepts of Ethnicity. Harvard University Press. p. 62. ISBN9780674157262. https://books.google.com/books?id=7Mkxdz_3d-oC&q=To%20be%20or%20to%20become%20an%20American&pg=PA62. "To be or to become an American, a person did not have to be of any particular national, linguistic, religious, or ethnic background. All he had to do was to commit himself to the political ideology centered on the abstract ideals of liberty, equality, and republicanism. Thus the universalist ideological character of American nationality meant that it was open to anyone who willed to become an American."
^Kaufmann, E. P. (1999). “American Exceptionalism Reconsidered: Anglo-Saxon Ethnogenesis in the "Universal" Nation, 1776–1850”. Journal of American Studies33 (3): 437–57. doi:10.1017/S0021875899006180. JSTOR27556685. https://eprints.bbk.ac.uk/4211/1/4211.pdf. "In the case of the United States, the national ethnic group was Anglo-American Protestant ("American"). This was the first European group to "imagine" the territory of the United States as its homeland and trace its genealogy back to New World colonists who rebelled against their mother country. In its mind, the American nation-state, its land, its history, its mission and its Anglo-American people were woven into one great tapestry of the imagination. This social construction considered the United States to be founded by the "Americans", who thereby had title to the land and the mandate to mould the nation (and any immigrants who might enter it) in their own Anglo-Saxon, Protestant self-image."
^Kaufmann, E. P. (1999). “American Exceptionalism Reconsidered: Anglo-Saxon Ethnogenesis in the "Universal" Nation, 1776–1850”. Journal of American Studies33 (3): 437–57. doi:10.1017/S0021875899006180. JSTOR27556685. https://eprints.bbk.ac.uk/4211/1/4211.pdf. "In the case of the United States, the national ethnic group was Anglo-American Protestant ("American"). This was the first European group to "imagine" the territory of the United States as its homeland and trace its genealogy back to New World colonists who rebelled against their mother country. In its mind, the American nation-state, its land, its history, its mission and its Anglo-American people were woven into one great tapestry of the imagination. This social construction considered the United States to be founded by the "Americans", who thereby had title to the land and the mandate to mould the nation (and any immigrants who might enter it) in their own Anglo-Saxon, Protestant self-image."
^Kaufmann, E. P. (1999). “American Exceptionalism Reconsidered: Anglo-Saxon Ethnogenesis in the "Universal" Nation, 1776–1850”. Journal of American Studies33 (3): 437–57. doi:10.1017/S0021875899006180. JSTOR27556685. https://eprints.bbk.ac.uk/4211/1/4211.pdf. "In the case of the United States, the national ethnic group was Anglo-American Protestant ("American"). This was the first European group to "imagine" the territory of the United States as its homeland and trace its genealogy back to New World colonists who rebelled against their mother country. In its mind, the American nation-state, its land, its history, its mission and its Anglo-American people were woven into one great tapestry of the imagination. This social construction considered the United States to be founded by the "Americans", who thereby had title to the land and the mandate to mould the nation (and any immigrants who might enter it) in their own Anglo-Saxon, Protestant self-image."
Farley, Reynolds (August 1991). “The New Census Question about Ancestry: What Did It Tell Us?”. Demography28 (3): 411–429. doi:10.2307/2061465. JSTOR2061465. PMID1936376.