Gutiérrez, J. F. (2010). Illuminating inequitable learning opportunities underlying effective collaborative problem solving in algebra. 

In P. Brosnan, Erchick, D., & Flevares, L. (Eds.), Proceedings of the Thirty-Second Annual Meeting of the North-American Chapter of the International Group for the Psychology of Mathematics Education (PME-NA 32) (Vol. VI, Ch. 2: Algebraic Thinking and Reasoning, p. 282). Columbus, OH: PME-NA.

Gutierrez-PMENA2010-proceedings.pdf