Methane Sources and Emissions
http://www.epa.gov/outreach/pdfs/Methane-and-Nitrous-Oxide-Emissions-From-Natural-Sources.pdf

United States Environmental Protection Agency


This site, published by the EPA, discusses the sources of methane emissions, including landfills, coal mining, the oceans and livestock, among others.

This resource is referenced here:
Subject: Environmental Science:Ecosystems:Biogeochemical cycling, Environmental Science:Energy:Fossil Fuels, Environmental Science:Waste:Waste Solid :Landfills,
Resource Type: Scientific ResourcesOverview/Reference Work
Theme: Teach the Earth:Course Topics:Environmental Science, Biogeoscience
Focus on the Cretaceous: Human Impacts
Geochemistry Applications: Environmental Geochemistry
Topics: Energy/Material cycles