Knapp, J. (1946). The Christmas cycle in symbols. [Catechetical Guild Educational Society].
Lua i Stíl Chicago (17ú heag.)Knapp, Justina. The Christmas Cycle in Symbols. St. Paul, Minn: [Catechetical Guild Educational Society], 1946.
Lua MLA (8ú heag.)Knapp, Justina. The Christmas Cycle in Symbols. [Catechetical Guild Educational Society], 1946.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.