Spencer, P. L., & Brydegaard, M. (1961). Building mathematical concepts in the elementary school.
Chicago Edition CitationSpencer, Peter Lineoln, and Marguerite Brydegaard. Building Mathematical Concepts in the Elementary School. 1961.
MLA Edition CitationSpencer, Peter Lineoln, and Marguerite Brydegaard. Building Mathematical Concepts in the Elementary School. 1961.
Warning: These citations may not always be 100% accurate.