Não informado. (1979). Focus on Learning Problems in Mathematics. Center for Teaching Learning on Mathematics.
Παραπομπή σε μορφή Chicago (17η εκδ.)Não informado. Focus on Learning Problems in Mathematics. Framingham, Mass: Center for Teaching Learning on Mathematics, 1979.
Παραπομπή σε μορφή MLA (8th εκδ.)Não informado. Focus on Learning Problems in Mathematics. Center for Teaching Learning on Mathematics, 1979.
Πρόσοχή: Οι παραπομπές μπορεί να μην είναι 100% ακριβείς.