Tietjen, M. L. (1976). The Bethlehem tree: A family Advent resource book. Paulist Press.
Lua i Stíl Chicago (17ú heag.)Tietjen, Mary Louise. The Bethlehem Tree: A Family Advent Resource Book. New York: Paulist Press, 1976.
Lua MLA (8ú heag.)Tietjen, Mary Louise. The Bethlehem Tree: A Family Advent Resource Book. Paulist Press, 1976.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.