Skala Kardashev
Catatan kaki

↑  Darling, David. "Kardashev, Nikolai Semenovich (1932-2019)". www.daviddarling.info. Diakses tanggal 2024-06-21.
1 2 3 4 5 6 7  Kardashev, N. S. (1964-10-01). "Transmission of Information by Extraterrestrial Civilizations". Soviet Astronomy. 8: 217. ISSN 0038-5301.
↑  "The Physics of Extraterrestrial Civilizations : Official Website of Dr. Michio Kaku". Diakses tanggal 2024-06-21.
↑  Zubrin, Robert (2000). Entering space: creating a spacefaring civilization (edisi ke-1. trade paperback ed). New York: Tarcher/Putnam. ISBN 978-1-58542-036-0. Pemeliharaan CS1: Teks tambahan (link)
↑  Kardashev, Nikolai S. (1980-07-01). "Strategies of Searching for Extraterrestrial Intelligence - A Fundamental Approach to the Basic Problem". Cosmic Search. 2: 36.
↑  Kardashev, Nikolai S. (1985).  Papagiannis, Michael D., ed. "On the Inevitability and the Possible Structures of Supercivilizations". The Search for Extraterrestrial Life: Recent Developments (dalam bahasa Inggris). Dordrecht: Springer Netherlands: 497–504. doi:10.1007/978-94-009-5462-5_65. ISBN 978-94-009-5462-5.
↑  Kardashev, N.S. (1997-03-01). "Cosmology and Civilizations". Astrophysics and Space Science (dalam bahasa Inggris). 252 (1): 25–40. doi:10.1023/A:1000837427320. ISSN 1572-946X.
↑  Davies, P. C. W. (2010). The eerie silence: renewing our search for alien intelligence (edisi ke-1st U.S. ed). Boston: Houghton Mifflin Harcourt. ISBN 978-0-547-13324-9. OCLC 432986059. Pemeliharaan CS1: Teks tambahan (link)
↑  "Cosmic Search Vol. 1, No. 1 - Little Green Men, White Dwarfs or Pulsars?". www.bigear.org. Diakses tanggal 2024-06-21.
↑  Basalla, George (2006). Civilized life in the universe: scientists on intelligent extraterrestrials. Oxford ; New York: Oxford University Press. ISBN 978-0-19-517181-5. OCLC 57641592.
↑  Galántai, Zoltan (2003-09-07). "Long Futures and Type IV Civilizations" (PDF). Diakses tanggal 2024-06-21.
1 2 3  Lemarchand, Guillermo A, Detectability of Extraterrestrial Technological Activities, Coseti .
1 2 3  
Kardashev, Nikolai (1964). "Transmission of Information by Extraterrestrial Civilizations" (PDF). Soviet Astronomy. 8: 217.
↑  Sagan, Carl (2000) [1973].  Jerome Agel, ed. Cosmic Connection: An Extraterrestrial Perspective. Freeman J. Dyson, David Morrison. Cambridge Press. ISBN 05-21-7830-38. Diakses tanggal 2008-01-01.  Parameter |month= yang tidak diketahui akan diabaikan (bantuan)
1 2  $$3121. (2005). "8". World Energy Outlook (PDF). Paris, France: International Energy Agency. hlm. 82. ISBN 92-64-1094-98. Diarsipkan dari versi asli (PDF) tanggal 2008-05-28. Diakses tanggal 2008-01-01.
↑  "Key World Energy Statistics" (PDF). International Energy Agency. 2004. Diarsipkan (PDF) dari versi asli tanggal 2006-05-24. Diakses tanggal 2006-08-10.
↑  Quad: 1 quadriliun BTU
↑  Kaku, Michio (2005). Parallel Worlds: The Science of Alternative Universes and Our Future in the Cosmos. New York: Doubleday. hlm. 317. ISBN 0713997281.
↑  "Type 6.0 Civilization". Beyond Universe Wiki (dalam bahasa Inggris). Diakses tanggal 2020-07-22.
↑  "Type Ultimate Civilization". Beyond Universe Wiki (dalam bahasa Inggris). Diakses tanggal 2020-07-22.
↑  Jack Cohen and Ian Stewart: Evolving the Alien: The Science of Extraterrestrial Life, Ebury Press, 2002, ISBN 0-09-187927-2