Não informado. (1979). Focus on Learning Problems in Mathematics. Center for Teaching Learning on Mathematics.
Chicago-referens (17:e uppl.)Não informado. Focus on Learning Problems in Mathematics. Framingham, Mass: Center for Teaching Learning on Mathematics, 1979.
MLA-referens (8:e uppl.)Não informado. Focus on Learning Problems in Mathematics. Center for Teaching Learning on Mathematics, 1979.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.