Adrienne_Citations

=Citations= 1. __The Usborne Illustrated Dictionary of Chemistry.__ London, England: Usborne Publishing Ltd, 2000.

2. __Helium.__ January 28, 2008. .

3. __It's Elemental: Helium.__ January 28, 2008. .

4. __Helium.__ January 28, 2008. .

5. __Helium(He).__ January 30, 2008. .