Não informado. (1969). Elements. University of Alberta, Department of Elementary Education.
Παραπομπή σε μορφή Chicago (17η εκδ.)Não informado. Elements. Alberta, Canada: University of Alberta, Department of Elementary Education, 1969.
Παραπομπή σε μορφή MLA (8th εκδ.)Não informado. Elements. University of Alberta, Department of Elementary Education, 1969.
Πρόσοχή: Οι παραπομπές μπορεί να μην είναι 100% ακριβείς.