Freitag, H. T., & Freitag, A. H. (1960). The number story. National Council of Teachers of Mathematics.
芝加哥风格引文Freitag, Herta Taussig, 与 Arthur H. Freitag. The Number Story. Washington: National Council of Teachers of Mathematics, 1960.
MLA引文Freitag, Herta Taussig, 与 Arthur H. Freitag. The Number Story. National Council of Teachers of Mathematics, 1960.
警告：这些引文格式不一定是100％准确.