text: * J. Day and R. F. Tylecote, The Industrial Revolution in Metals (The Institute of Metals, London 1991).
  * Söderberg, A. 2011. [http://web.comhem.se/vikingbronze/soderberg_situne_dei_2011.pdf Eyvind Skáldaspillir's silver - refining and standards in pre-monetary economies in the light of finds from Sigtuna and Gotland]. Situne Dei 2011. Edberg, R. Wikström, A. (eds). Sigtuna.
  * R. F. Tylecote, A history of metallurgy (Institute of materials, London 1992).
  * [http://www.ncl.ac.uk/library/specialcollections/collections/daguerreotypes/pattinson.php Newcastle University: Hugh Lee Pattinson]