http://www.periodictable.com/Elements/079/data.html
http://www.rsc.org/periodic-table/element/79/gold
https://answers.yahoo.com/question/index?qid=20071207203901AAFl4hU
http://www.sfmuseum.org/hist2/gold.html
http://education.jlab.org/itselemental/ele079.html
http://www.newton.dep.anl.gov/askasci/chem07/chem07305.htm
http://www.ptable.com/
http://www.rsc.org/periodic-table/element/79/gold
https://answers.yahoo.com/question/index?qid=20071207203901AAFl4hU
http://www.sfmuseum.org/hist2/gold.html
http://education.jlab.org/itselemental/ele079.html
http://www.newton.dep.anl.gov/askasci/chem07/chem07305.htm
http://www.ptable.com/