Cita APA (7th ed.)

Freitag, H. T., & Freitag, A. H. (1960). The number story. National Council of Teachers of Mathematics.

Cita Chicago (17th ed.)

Freitag, Herta Taussig, i Arthur H. Freitag. The Number Story. Washington: National Council of Teachers of Mathematics, 1960.

Cita MLA (8th ed.)

Freitag, Herta Taussig, i Arthur H. Freitag. The Number Story. National Council of Teachers of Mathematics, 1960.