POLIS, A. R., & BEARD, E. M. (1973). Fundamental mathematics for elementary teachers: A behavioral objectives approach. Harper and Row.

POLIS, A. Richard, and Earl M. BEARD. Fundamental Mathematics for Elementary Teachers: A Behavioral Objectives Approach. New York: Harper and Row, 1973.

POLIS, A. Richard, and Earl M. BEARD. Fundamental Mathematics for Elementary Teachers: A Behavioral Objectives Approach. Harper and Row, 1973.