Florida-Spectrum Environmental Services
Florida Spectrum: Chemical Fact Sheet: Rhenium
Excellent summary of the basics on rhenium.
Florida-Spectrum Environmental Services
Florida Spectrum: Chemical Fact Sheet: Selenium
Nice detailed synopsis of selenium, its properties and uses.
Other
Chemical elements.com/scandium
A site containing a good deal of elemental information. Information on each element includes atomic number, atomic mass, melting point, boiling point, density, isotopes and more.
National Institutes of Health
National Institutes of Health: Dietary Supplement Fact Sheet: Selenium
Information on the dietary and nutritional significance of selenium from an authoritative source.
University of Kentucky
The Comic Book Periodic Table of Elements: Scandium
This site may focus on fun, rather than facts, but it will become a favorite of any Chemistry student. Here you will find scanned images of panels and/or pages of comic books, with references to the element you seek.