Langlois, C., & Seignobos, C. Introduction to the Study of History. Holt and Company.
Lua i Stíl Chicago (17ú heag.)Langlois, Ch.V, agus Ch Seignobos. Introduction to the Study of History. New York: Holt and Company.
Lua MLA (8ú heag.)Langlois, Ch.V, agus Ch Seignobos. Introduction to the Study of History. Holt and Company.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.