Study | Drivers of the US CO2 emissions 1997–2013 (open access) User avogadros_number, in the GlobalClimateChange: How and Why Earth's Climate Changes subreddit, 28 Jul 2015
Drivers of the US CO2 emissions 1997-2013 User the_ultravixens, in the /r/Energy: News & Discussion subreddit, 27 Jul 2015