APA (7th ed.) Citation

Heddens, J. W., & Smith, M. L. (1971). Today's mathematics: A guide to concepts and methods in elementary school mathematics (2d ed.). Science Research Associates, Inc..

Chicago Style (17th ed.) Citation

Heddens, James W., and Marge L. Smith. Today's Mathematics: A Guide to Concepts and Methods in Elementary School Mathematics. 2d ed. Palo Alto, Calif.: Science Research Associates, Inc., 1971.

MLA (9th ed.) Citation

Heddens, James W., and Marge L. Smith. Today's Mathematics: A Guide to Concepts and Methods in Elementary School Mathematics. 2d ed. Science Research Associates, Inc., 1971.