Abraxas Petroleum Corporation [AXAS]
Altek Power Corporation [APKKF.PK]
Altex Industries, Inc. [ALTX.OB]
American Oil & Gas, Inc. [AEZ]
Americas Power Partners, Inc. [APPN.PK]
Anadarko Petroleum Corporation [APC]
Apache Corporation [APA]
Apco Argentina Inc. [APAGF]
Aspen Exploration Corporation [ASPN.OB]
ATP Oil & Gas Corporation [ATPG]

Barnwell Industries, Inc. [BRN]
Basic Earth Science Systems, Inc. [BSIC.OB]
Bayou City Exploration, Inc. [BYCX.OB]
Baytex Energy Trust [BTE]
Berry Petroleum Company [BRY]
Blue Dolphin Energy Company [BDCO]
Brigham Exploration Company [BEXP]

Cabot Oil & Gas Corporation [COG]
Callon Petroleum Company [CPE]
Canadian Natural Resources Limited [CNQ]
Carrizo Oil & Gas, Inc. [CRZO]
Chesapeake Energy Corporation [CHK]
China Petroleum & Chemical Corporation [SNP]
Cimarex Energy Co. [XEC]
CKX Lands, Inc. [CKX]
Clayton Williams Energy, Inc. [CWEI]
CNOOC Limited [CEO]
Comstock Resources, Inc. [CRK]
Contango Oil & Gas Company [MCF]
Continental Energy Corporation [CPPXF.OB]
CREDO Petroleum Corporation [CRED]
Crimson Exploration, Inc. [CXPO.OB]
Crosstex Energy, L.P. [XTEX]

Delta Petroleum Corporation [DPTR]
Denbury Resources Inc. [DNR]
Devon Energy Corporation [DVN]
Double Eagle Petroleum Co. [DBLE]

Empire Energy Corporation International [EEGC.OB]
Enbridge Energy Management, L.L.C. [EEQ]
Encore Acquisition Company [EAC]
Endeavour International Corporation [END]
Energy Partners, Ltd. [EPL]
Enterprise Products Partners L.P. [EPD]
EOG Resources, Inc. [EOG]
ERHC Energy Inc. [ERHE.OB]
Evolution Petroleum Corporation [EPM]
EXCO Resources, Inc. [XCO]

Far East Energy Corporation [FEEC.OB]
FEC Resources, Inc. [FECOF.OB]
FieldPoint Petroleum Corporation [FPP]
Forest Oil Corporation [FST]

Gasco Energy, Inc. [GSX]
GeoPetro Resources Company [GPR]
GeoResources, Inc. [GEOI]
GMX Resources Inc. [GMXR]
Goodrich Petroleum Corporation [GDP]
Gulfport Energy Corporation [GPOR]

Hallador Petroleum Company [HPCO.OB]
Harvest Natural Resources, Inc. [HNR]
HKN, Inc. [HKN]
Houston American Energy Corp. [HUSA]

International Power plc [IPRPY.PK]
Isramco, Inc. [ISRL]

Linn Energy, LLC [LINE]
Lucas Energy, Inc. [LEI]

Magellan Petroleum Corporation [MPET]
Martin Midstream Partners L.P. [MMLP]
Maxim Power Corp. [MXGFF.PK]
McMoRan Exploration Co. [MMR]
Mexco Energy Corporation [MXC]

Newfield Exploration Company [NFX]
Noble Energy, Inc. [NBL]

Oakridge Energy, Inc. [OAKR.OB]
Occidental Petroleum Corporation [OXY]

Panhandle Oil and Gas Inc. [PHX]
Parallel Petroleum Corporation [PLLL]
Penn Virginia Corporation [PVA]
PetroQuest Energy, Inc. [PQ]
Pioneer Natural Resources Company [PXD]
Plains Exploration and Production Company [PXP]
PrimeEnergy Corporation [PNRG]
Provident Energy Trust [PVX]

Questar Corporation [STR]
Quicksilver Resources Inc. [KWK]

Range Resources Corporation [RRC]
Rocky Mountain Minerals, Inc. [RMMI.OB]
Rosetta Resources Inc. [ROSE]
Royale Energy, Inc. [ROYL]

Southwestern Energy Company [SWN]
Spindletop Oil & Gas Co. [SPND.OB]
St. Mary Land & Exploration Company [SM]
Stone Energy Corporation [SGY]
Suncor Energy Inc. [SU]
Swift Energy Company [SFY]

Talisman Energy Inc. [TLM]
Texas Vanguard Oil Company [TVOC.OB]
The Meridian Resource Corporation [TMR]
The Reserve Petroleum Company [RSRV.OB]
Toreador Resources Corporation [TRGL]
TransGlobe Energy Corporation [TGA]

Ultra Petroleum Corp. [UPL]

VAALCO Energy, Inc. [EGY]

Williams Pipeline Partners L.P. [WMZ]

XTO Energy Inc. [XTO]