@book{133506,
	author = {Cramer, B. and Federal Institute for Geosciences and Natural Resources (Alemania) and World Petroleum Congress (16th. : 2000 jun. 11-15 : Calgary, Alberta, Canada) and Faber, E. and Federal Institute for Geosciences and Natural Resources (Alemania)},
	title = {New isotope geochemical concepts for natural gas exploration}
}