Look for books and other items in libraries near and far. Most items you find may be requested through Interlibrary Loan.
The Ethics of the Global Environment
Beyond the Land Ethic: More Essays in Environmental Philosophy
Ethics for a Small Planet: New Horizons On Population, Consumption, and Ecology
Living in Integrity: A Global Ethic to Restore a Fragmented Earth: Studies in Social, Political, and Legal Philosophy
The Rights of Nature: A History of Environmental Ethics: History of American Thought and Culture
Google Books is a great resource for finding books and gives a preview of what the book is about and often short sections to view.
There is a link to see if your local library library owns the book and you can see if any of the local libraries have the book!