APA (7th ed.) Zitazioa
(2012). Natural gas information 2012: With 2011 data. OECD.
Chicago Style (17th ed.) Zitazioa
Natural Gas Information 2012: With 2011 Data. [Place of publication not identified]: OECD, 2012.
MLA (9th ed.) Zitazioa
Natural Gas Information 2012: With 2011 Data. OECD, 2012.
Kontuz: berrikusi erreferentzia hauek erabili aurretik.