Purpel, D. E. (1989). The moral & spiritual crisis in education: A curriculum for justice and compassion in education. Bergin & Garvey.
Lua i Stíl Chicago (17ú heag.)Purpel, David E. The Moral & Spiritual Crisis in Education: A Curriculum for Justice and Compassion in Education. Granby, Mass: Bergin & Garvey, 1989.
Lua MLA (9ú heag.)Purpel, David E. The Moral & Spiritual Crisis in Education: A Curriculum for Justice and Compassion in Education. Bergin & Garvey, 1989.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.