There are a few books that can also help organizations conduct their own self sustainability assessments. Here are the top recommended sustainability assessment books;
Flawless Consulting, Peter Block: This is a classic book on conducting assessments for any topic. It was published more than a decade ago and still highly relevant.
Sustainability Assessment: Criteria and Processes, Robert Gibson: A book specifically on conducting sustainability assessments.
Corporate Sustainability Planning Assessment Guide: A Comprehensive 
Organizational Assessment, Donald Fisher: This manual is designed to serve as a guide for an organization s self-assessment on its corporate sustainability efforts.
Business Guide to Sustainability, Darcy Hitchcock and Marsh Willard: Winner of Choice Magazine – Outstanding Academic Titles for 2007 in Sustainability category. Both Marsha and Darcy are sustainability consultants and the book discusses each primary of an organization and provides their SCORE assessment tool for each primary department and division.