Curriculum Materials

Sowder, J. et al. (2007).  Reasoning about Numbers and Quantities.  W. H. Freeman. (prepublication copy)
Schifter, D., Bastable, V., & Russell, S.J. (1999). 
Number and operations, part I:  Building a system of tens.  Parsippany, NJ: Dale Seymour.
Reys, Lindquist, Lambdin, Smith, &  Suydam (2007).   Helping Children Learn Mathematics.  John Wiley & Sons.
Lampert, M. (2001).  Teaching problems and the problems of teaching.  New Haven, CT:  Yale University.