1. Corporations active
   1. - BP
   2. -Statoil
   3. - Sinopec
   4. - EnCana
   5. - Korea Gas Corp.
   6. - Imperial Oil Ltd.
   7. - PGNiG (Poland)
   8. - Carrizo Oil & Gas (active in Marcellus)
2. Ressource
   1. Reservebasis
      1. Reserve
3. Institutes
   1. GFZ
   2. IFP
   3. TNO
4. Authorities
   1. EIA
   2. USGS
   3. IEA
   4. EPA
   5. FERC
      1. #04231312 on US reserves
   6. BGS
   7. BGR
      1. #04271352 on German reserves
   8. DOE
5. Academic
   1. GASH
      1. #03311218
   2. PGI
6. Companies
   1. The BIG ONES
      1. Shell
         1. Sweden
         2. Ukraine
      2. Chevron
         1. Poland
      3. Total
         1. France
         2. Denmark
      4. ExxonMobil
         1. Germany
         2. Poland
         3. Hungary
      5. ConocoPhillips
         1. Poland
      6. MarathonOilCorp
         1. Poland
      7. TalismanEnergy
         1. Poland
      8. OMV
         1. Austria
      9. Chesapeake Energy
      10. Devon
      11. BP
   2. Explorers
      1. XTO
      2. Schlumberger
      3. LaneEnergy
      4. SanLeonEnergy PLC
      5. IGAS
         1. Northern England
      6. FalconOil&Gas
         1. Hungary
      7. Halliburton
7. Economists
   1. The Economist
8. Trade Organizations
   1. US Potential Gas Committee
   2. NGSupplyAssociation
   3. CleanSkies
   4. DGMK