Não informado. (1979). Focus on Learning Problems in Mathematics. Center for Teaching Learning on Mathematics.
Citação do estilo Chicago (17ª ed.)Não informado. Focus on Learning Problems in Mathematics. Framingham, Mass: Center for Teaching Learning on Mathematics, 1979.
Citação MLA (8ª ed.)Não informado. Focus on Learning Problems in Mathematics. Center for Teaching Learning on Mathematics, 1979.
警告：这些引文格式不一定是100％准确.