Eibling, H. H., & Jackson, C. J. (1977). Two centuries of progress: United States history. Laidlaw brothers.
Lua i Stíl Chicago (17ú heag.)Eibling, Harold H., agus Carlton J. Jackson. Two Centuries of Progress: United States History. Irvine: Laidlaw brothers, 1977.
Lua MLA (9ú heag.)Eibling, Harold H., agus Carlton J. Jackson. Two Centuries of Progress: United States History. Laidlaw brothers, 1977.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.