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.
Earthquakes tied to injection wells handling fracking wastes will again be in the spotlight this week.
A team of scientists from the U.S. Geological Survey will present its findings on Wednesday at a national seismologist conference in California.
The analysis will focus of earthquakes in the Colorado-New Mexico border area, central and southern Oklahoma and near Guy, Ark.
Ohio has had 13 small earthquakes near a now-closed injection well near Youngstown in 2011-2012. The largest quake was a 4.0-magnitude quake on Dec. 31.
But the Youngstown quakes are not part of the federal study, but the circumstances are very similar, experts have said.