National Council of Teachers of Mathematics, Schoen, H. L., & Zweng, M. (1986). Estimation and mental computation: 1986 yearbook. NCTM.
Chicago Style (17th ed.) CitationNational Council of Teachers of Mathematics, Harold L. Schoen, and Marilyn Zweng. Estimation and Mental Computation: 1986 Yearbook. Reston, VA: NCTM, 1986.
MLA (9th ed.) CitationNational Council of Teachers of Mathematics, et al. Estimation and Mental Computation: 1986 Yearbook. NCTM, 1986.
Warning: These citations may not always be 100% accurate.