Bibliography
"Researchers may have found a Viking sunstone."
CBSNews. CBS Interactive, 8 Mar. 2013. Web. 26 Nov.
2013.
<http://www.cbsnews.com/news/researchers-may-have-found-a-viking-sunstone/>.
"Sunstone (medieval)."
<i>Wikipedia</i>. Wikimedia Foundation,
25 Oct. 2013. Web. 26 Nov. 2013.
<http://en.wikipedia.org/wiki/Sunstone_(medieval)>.
Ropars, Guy, Gabriel Gorre, Albert Le Floch, Jay
Enoch, and Vasudevan Lakshminarayanan. "A
depolarizer as a possible precise sunstone for
Viking navigation by polarized skylight." Proceedings
of the Royal Society 468.2139 (2011): 15. Proceedings
of the Royal Society. Web. 20 Nov. 2013.
Ghosh, Gorachand. "Dispersion-equation
coefficients for the refractive index and
birefringence of calcite and quartz crystals." Optics
Communications 163.1-3 (1999): 8. Science
Direct. Web. 20 Nov. 2013.
"Calcite." Wikipedia. Wikimedia Foundation,
11 Dec. 2013. Web. 25 Nov. 2013.
<http://en.wikipedia.org/wiki/Calcite>.
U.S. Department of The Interior. Bureau of Mines. Iceland
Spar and Optical Flourite. By H. Herbert.
Washington: Government Printing Office, February
1931. (United States Department of the Interior I.
C. 6468). (I 28.27:6468).
Le Floch, Albert, Guy Ropars, Jay Enoch, and
Vasudevan Lakshminarayanan. "The polarization sense
in human vision." Vision Research 50.20 (2010): 5.
Science Direct. Web. 20 Nov. 2013.
"Polariscope." The Gemology Project. GemologyOnline,
12 Nov. 2012. Web. 27 Nov. 2013.
<http://gemologyproject.com/wiki/index.php?title=Polariscope>.