ChemGlobe: Europium
- Electronic, thermal, and steric data along with isotopes table.
- http://partisans.spurious.biz/~pkremer/projects/chemglobe/ptoe/_/63.html

LANL: Europium
- History, production, properties, sources, and uses.
- http://periodic.lanl.gov/elements/63.html

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

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

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

ChemicalElements.com: Europium
- Basic information, atomic structure, and isotopes.
- http://www.chemicalelements.com/elements/eu.html

It's Elemental: Europium
- Basic physical and historical information.
- http://education.jlab.org/itselemental/ele063.html

Visual Elements: Europium
- Image, source, physical information, and key isotopes.
- http://www.chemsoc.org/viselements/pages/europium.html