4[1]American Gas Association (1997): Survey of Underground Storage of Natural Gas in the United States and Canada 1996, Arlington, Virginia, USA
5[2]Economic Commission for Europe (UN/ECE) (1999): underground Storage in Europe and Central Asia, Survey 1996-1999, Geneva Enseling, G. (1999): Auswirkungen der Liberalisierung
6[3]Hirschhausen, H. (1996): Untersuchung der wesentlichen technischen und wirtschaftlichen Faktoren der Erdgasspeicherung, Dissertation TU Clausthal
7[4]Eric R. King,Dax D. Junker,Developments in Underground Gas Storage,http://www.gablelaw.com/documents
8[5]James Tobin ,James Thompson,Natural Gas Storage in the United States in 2001: A Current Assessment and Near-Term outlook,http://tonto.eia.doe.gov/FTPROOT/features
9[6]Academic report: Gas Storage in the APEC Region,http://www.ieej.or.jp/aperc/2002pdf
10American Gas Association (1997): Survey of Underground Storage of Natural Gas in the United States and Canada, Arlington, Virginia, USA, 1996.
