Caldwell, I. S. (1959). The organizing principle in the curriculum of Christian education: Protestant trends.
Lua i Stíl Chicago (17ú heag.)Caldwell, Irene Smith. The Organizing Principle in the Curriculum of Christian Education: Protestant Trends. 1959.
Lua MLA (8ú heag.)Caldwell, Irene Smith. The Organizing Principle in the Curriculum of Christian Education: Protestant Trends. 1959.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.