IL-Constructivism and IL
Scardamalia, M., & Bereiter, C. (2003). Knowledge building environments: Extending the limits of the possible in education and knowledge work. In A. DiStefano, K.E. Rudestam, & R. Silverman (Eds.), Encyclopedia of distributed learning. Thousand Oaks, CA: Sage Publications.
Accessed from http://www.ikit.org/fulltext/2003_KBE.pdf
This article provides thorough and clear definitions of concepts relating to knowledge building environments, including some history into how they developed and what they are good for. I found it extremely helpful as a starting point for my study of this subject.