How to use Summed-area Tables way in OpenGL

Every freind:
I encounter a difficult in OpenGL. I want to use the way of summed-area tables in texture mapping. I know there is mipmap filter as texture mapping. but at present I think over using summed-area tables algorithms to perform maping. Who can tell me how to do this. If send me source code of realizaon this algorithms in OpenGL. Thank a lot! a lot. My email adress :