APA (7th ed.) Citation

Heddens, J. W., & Smith, M. L. (1968). Today's mathematics: A guide to concepts and methods in elementary school mathematics. Science Research Associates.

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. Chicago: Science Research Associates, 1968.

MLA (9th ed.) Citation

Heddens, James W., and Marge L. Smith. Today's Mathematics: A Guide to Concepts and Methods in Elementary School Mathematics. Science Research Associates, 1968.