Não informado. University of Iowa studies in education. University of Iowa, College of Education.
Παραπομπή σε μορφή Chicago (17η εκδ.)Não informado. University of Iowa Studies in Education. Iowa City, Iowa: University of Iowa, College of Education.
Παραπομπή σε μορφή MLA (8th εκδ.)Não informado. University of Iowa Studies in Education. University of Iowa, College of Education.
Πρόσοχή: Οι παραπομπές μπορεί να μην είναι 100% ακριβείς.