I kinda liked the changes made by anon. But we can consider them later. I collapsed the template.

I did check out the article on Kaziranga National Park. I learned something new: the Main article link is indeed useful, but in a very specific circumstance: when there is an article already in existence that directly enlarges the subsection in question. For example, the subsection on Fauna is linked to a larger and more detailed article on the fauna of this national park. Another example is the article on Buckingham Palace. The subsection on The Garden and the Mews has a Main link to an article specifically dealing with the Buckingham Palace garden. In Sustainability, this is not the case, and there is often redundancy: for example, Main link points to acid rain and climate change when in fact that subsection already has those articles embedded in the text. 

The book is Principles of Sustainability, by Simon Dresner, 2002. The paperback is coming next month, but the hardback should be easy to get thru the library. I took a peek via Amazon, and it looks like most of the book is a very detailed history of the concept. It appears that it was actually the World Council of Churches that originated the term.