Vegetative Roof Systems (Green Roofs)
1. General: For an in-depth general article about vegetative roof systems, see this page at the Whole Building Design Guide site, which is maintained by the National Institute of Building Sciences. It's a very good page.
2. General: Green Roofs for Healthy Cities provides extensive information about vegetative roof systems; you should note that they are an advocacy group which describes itself as a "not-for-profit industry association working to promote the industry throughout North America". (Quote taken from their website).
4. Standards: The 2002 version of FLL - Guidelines for the Planning, Execution, and Upkeep of Green Roof Sites can be viewed on the website of Io Contracts Ltd. This guide (the 2002 version is now out-of-date, but still pretty informative) is produced by the German Landscaping and Landscape Development Research Society (FLL) and is a detailed, comprehensive effort at creating standards for all aspects of green roofing. The current version, extensively revised and updated, is available for sale at the FLL website.
5. Standards: "The GRO Green Roof Code - Green Roof Code of Best Practice for the UK 2014" is based on the German FLL Guidelines, adapted for the UK market. Available on the website of the National Federation of Roofing Contractors Limited.
6. Technical: How much do you want to know about green roofs? A lot? A whole lot? In exhaustive detail? This is your book: Green Roof Systems: A Guide to the Planning, Design, and Construction of Landscapes over Structure, by Susan K. Weiler and Katrin Scholz-Barth.
7. Technical: "Using Garden Roof Systems to Achieve Sustainable Building Envelopes" looks into the thermal performance and storm water retention aspects of vegetative roof systems. Available on the website of the National Research Council Canada.
8. Technical: "A Comparative Study of Three Growing Media and Four Plant Groups Under Extensive Green Roof Conditions in San Luis Obispo, California" by Todd A. Nelson contains a wealth of precise information about green roofs that actually goes far beyond what the title of the article indicates. It's available at the Digital Commons section of the California Polytechnic State University website.