ChemGlobe: Ruthenium
- Electronic, thermal, and steric data along with an isotope table.
- http://partisans.spurious.biz/~pkremer/projects/chemglobe/ptoe/_/44.html

LANL: Ruthenium
- History, sources, uses, and properties.
- http://periodic.lanl.gov/elements/44.html

Wikipedia: Ruthenium
- Properties of the element, including its history, applications, and characteristics.
- http://en.wikipedia.org/wiki/Ruthenium

Lenntech: Ruthenium
- Physical data, chemical properties, and health effects.
- http://www.lenntech.com/Periodic-chart-elements/Ru-en.htm

EnvironmentalChemistry.com: Ruthenium
- Atomic structure, chemical and physical properties, and table of nuclides.
- http://environmentalchemistry.com/yogi/periodic/Ru.html

It's Elemental: Ruthenium
- Basic physical and historical information.
- http://education.jlab.org/itselemental/ele044.html

ChemicalElements.com: Ruthenium
- Basic information, atomic structure, and table of isotopes.
- http://www.chemicalelements.com/elements/ru.html

Visual Elements: Ruthenium
- Image, discovery, uses, source, and physical information.
- http://www.chemsoc.org/viselements/pages/ruthenium.html