http://www.educationworld.com/a_curr/curr146.shtml

http://nrich.maths.org/4770

http://www.michigan.gov/documents/mde/Writing_to_Learn_Mathematics_306722_7.pdf

http://www.nctm.org/standards/content.aspx?id=23273 guiding principles

http://www.edcc.edu/mac/ MAC project

http://wac.colostate.edu/journal/vol9/russek.pdf writing to learn mathematics

http://math.unipa.it/~grim/21_project/21_charlotte_WillsonPaper.pdf