In no particular order, except how I found them. Hope they are useful.

Yalie at 2nd intersessional meeting
Pace U Green Law Take
Woodrow Wilson apparently got scholars writing about this
Rio+20 Building the Peoples Summit
Transnational Institute
Climate talk with Alberto Gomez
The Sustainable Cities Working Group’s Submission to the Secretariat of the UN for the “Rio +20 Earth Summit”
NRDC's Submission to the Secretariat of the UN for the "Rio+20 Earth Summit"
You can take it to the (NDRC) bank