Key points are not available for this paper at this time.
Kimberly Hufferd-Ackles, Karen C. Fuson, Miriam Gamoran Sherin, Describing Levels and Components of a Math-Talk Learning Community, Journal for Research in Mathematics Education, Vol. 35, No. 2 (Mar., 2004), pp. 81-116
Hufferd-Ackles et al. (Mon,) studied this question.