Não informado. (1977). Core: Collected original resources in education. Carfax Publishing.
Παραπομπή σε μορφή Chicago (17η εκδ.)Não informado. Core: Collected Original Resources in Education. Oxford, Inglaterra: Carfax Publishing, 1977.
Παραπομπή σε μορφή MLA (8th εκδ.)Não informado. Core: Collected Original Resources in Education. Carfax Publishing, 1977.
Πρόσοχή: Οι παραπομπές μπορεί να μην είναι 100% ακριβείς.