Jones, D.A. (1991), "Electrical engineering: the backbone of society", Proceedings of the IEE: Science, Measurement and Technology, 138 (1): 1–10, doi:10.1049/ip-a-3.1991.0001
Moller, Peter; Kramer, Bernd (December 1991), "Review: Electric Fish", BioScience, American Institute of Biological Sciences, 41 (11): 794–6 [794], doi:10.2307/1311732, JSTOR1311732
Chalmers, Gordon (1937), "The Lodestone and the Understanding of Matter in Seventeenth Century England", Philosophy of Science, 4 (1): 75–95, doi:10.1086/286445
Danish Ministry of Environment and Energy, "F.2 The Heat Supply Act", Denmark's Second National Communication on Climate Change, diarsipkan dari versi asli tanggal 2008-01-08, diakses tanggal 2007-12-09
Danish Ministry of Environment and Energy, "F.2 The Heat Supply Act", Denmark's Second National Communication on Climate Change, diarsipkan dari versi asli tanggal 2008-01-08, diakses tanggal 2007-12-09