Bentor, Yinon

Chemical Element.com-Yttrium

<http://www.chemicalelements.com/elements/y.html>

February 7, 2000

Ehrenberg, April

Yttrium

<http://gilligan.esu7.k12.ne.us/~lweb/Lakeview/science/y.htm>

February 7, 2000

Matrin, Neal

Yttirum

January 7, 2000

<http://pearl1.lanl.gov/periodic/elements/39.html>

February 7, 2000

Valentin, Ivonne

Yttrium

<http://marian.creighton.edu/~spod/yttrium.html>

February 7, 2000

Winter, Mark

Web Element.com-Yttrium

16 December 1999

         <http://www.webelements.com/webelements/elements/text/key/Y.html>

February 7, 2000