This portion covers the Nature of and Assumptions of Critical Theory...essentially from a "postmodern" perspective. Although I would personally cite other references, the authors have...in my opinion...generally captured the essence of Critical Theory and as such, is a very concise statement of it.
The main source for the material is:
Kincheloe, J. L., & McLaren, P. L. (1994). Rethinking critical theory and qualitative research. In N. K. Denzin & Y. S. Lincoln (Eds.), Handbook of qualitative research (pp. 138-157). Thousand Oaks, CA: Sage
The pages presented here are jpg images and may be difficult to directly print out. I suggest downloading the image and adjusting your Print Properties accordingly.