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.
The Ohio Department of Natural Resources' Division of Oil & Gas Resources Management has approved seven new permits for Utica shale drilling.
That brings Ohio's total through Feb. 9 to 518 permits.
Of that total, 236 wells have been drilled and 65 are in production.
A total of 28 drilling rigs are working in Ohio.
The new permits are: four in Carroll County, two in Belmont County and one in Columbiana County.