Keen, M. H. (1967). A history of Medieval Europe. Routledge & Paul.
Lua i Stíl Chicago (17ú heag.)Keen, Maurice Hugh. A History of Medieval Europe. London: Routledge & Paul, 1967.
Lua MLA (9ú heag.)Keen, Maurice Hugh. A History of Medieval Europe. Routledge & Paul, 1967.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.