APA

Gerling P., Kockel F., Federal Institute for Geosciences and Natural Resources (Alemania), World Petroleum Congress (15th. : 1997 : Beijing), Kockel F. & Federal Institute for Geosciences and Natural Resources (Alemania).Deep natural gas. : .

Chicago

Gerling P, Kockel F, Federal Institute for Geosciences and Natural Resources (Alemania), World Petroleum Congress (15th. : 1997 : Beijing), Kockel F and Federal Institute for Geosciences and Natural Resources (Alemania).Deep natural gas. : .

Harvard

Gerling P., Kockel F., Federal Institute for Geosciences and Natural Resources (Alemania), World Petroleum Congress (15th. : 1997 : Beijing), Kockel F. and Federal Institute for Geosciences and Natural Resources (Alemania).Deep natural gas. : .

MLA

Gerling P, Kockel F, Federal Institute for Geosciences and Natural Resources (Alemania), World Petroleum Congress (15th. : 1997 : Beijing), Kockel F and Federal Institute for Geosciences and Natural Resources (Alemania).: . .