Bibliography:
Bentor, Yinon. "Chemical Elements.com - Neptunium (Np)." Chemical Elements.com. Yinon Bentor, 2012. Web. 20 Mar. 2013.
"Neptunium - Element Information." Rsc.org. Royal Society of Chemistry, 2013. Web. 20 Mar. 2013.
"Neptunium." Chemicool.com. Chemicool.com, 2013. Web. 20 Mar. 2013.
"Neptunium." The World Book Encyclopedia. Chicago, IL: World Book, 2012. N. pag. Print.
Weiss, P. "Little-studied Metal Goes Critical. (Neptunium Nukes?)." InfoTrac. N.p., 26 Oct. 2002. Web. 24 Mar. 2013.
Bentor, Yinon. "Chemical Elements.com - Neptunium (Np)." Chemical Elements.com. Yinon Bentor, 2012. Web. 20 Mar. 2013.
"Neptunium - Element Information." Rsc.org. Royal Society of Chemistry, 2013. Web. 20 Mar. 2013.
"Neptunium." Chemicool.com. Chemicool.com, 2013. Web. 20 Mar. 2013.
"Neptunium." The World Book Encyclopedia. Chicago, IL: World Book, 2012. N. pag. Print.
Weiss, P. "Little-studied Metal Goes Critical. (Neptunium Nukes?)." InfoTrac. N.p., 26 Oct. 2002. Web. 24 Mar. 2013.