Chesapeake Energy Corp,the Oklahoma-based firm is the No. 1 driller in Ohio.
Rig Count Interactive Map by Baker Hughes, an energy services company.
Shale Sheet Fracking, a Youngstown Vindicator blog.
The Ohio Environmental Council, a statewide eco-group based in Columbus.
Earthjustice, a national eco-group.
People's Oil and Gas Collaborative-Ohio, a grass-roots group in Northeast Ohio.
Concerned Citizens of Medina County, a grass-roots group.
No Frack Ohio, a Columbus-based grass-roots group.
Fracking: Gas Drilling's Environmental Threat by ProPublica, an online journalism site.
Pipeline, blog from Pittsburgh Post-Gazette on Marcellus shale drilling.
Allegheny Front, environmental public radio for Western Pennsylvania.
Oklahoma-based Devon Energy Corp. has agreed to sell 30 percent of its interest in the oil-rich Cline and Midland-Wolfcamp shales in West Texas.
The buyer is Japan's Sumitoma Corp. in a deal that is valued at $1.4 billion, the Wall Street Journal reported on Thursday.
The deal involves about 650,000 net acres.
In January, Devon Energy inked a $2.2 billion deal on five shale tracts with China-based Sinopec International Petroleum Exploration & Production Corp.