1. EIA. Natural gas annual, 2011.http://www.eia.gov/naturalgas/annual/.
2. EIA. Technically recoverable shale oiland shale gas resources:An assessment of 137 shale formations in 41 countries outside theUnited States. http://www.eia.gov/analysis/studies/worldshalegas/.
3. Pore structure characterization of North American shale gas reservoirs using USANS/SANS, gas adsorption, and mercury intrusion
4. Passey, Q. R.; Bohacs, K. M.; Esch, W. L.; Klimentidis, R.; Sinha, S.International Oil and Gas Conference and Exhibition in China, Beijing, China, June 8–10, 2010;Society of Petroleum Engineers:Kuala Lumpur, Malaysia, 2010; SPE Paper No. 131350.