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.
Bloomberg News reports that Warren Buffett's Burlington Northern Santa Fe railroad and Union Pacific Corp. are fighting a drop in coal prices by catering to drillers in shale regions.
The railroads are increasingly hauling drilling equipment.
BNSF's petroleum carloads rose 75 percent in the second quarter, while Union Pacific saw a 12 percent gain in fracking-related freight, Bloomberg reported on Thursday.
The Union Pacific said it expects that its business will grow to almost 400,000 shale-related carloads in 2012.
Analysts said it is new growth area for railroads, although rail shipments may drop after more pipelines are completed to move oil, natural gas and ethanes, propanes and butanes..