Organisation for Economic Co-operation and Development
OECD, 1974
Buku Teks
Cassedy, Edward S., author
Cambridge University Press, 2000
Buku Teks
Asean -Ec Energy Management Training and Research Centre, 1993,
Buku Referensi
Endro Utomo Notodisuryo
Jakarta: Energy conservation workshop, 1996,
Buku Referensi
Pohan, Hazairin, author
Jurnal Kajian Wilayah Eropa, 2008
Artikel Jurnal