ChemicalElements.com: Europium
Basic information, atomic structure, and isotopes.
EnvironmentalChemistry.com: Europium
Atomic structure, chemical and physical properties, and table of nuclides.
It's Elemental: Europium
Basic physical and historical information.
LANL: Europium
History, production, properties, sources, and uses.
Lenntech: Europium
Physical data, chemical properties, health and environmental effects.
Visual Elements: Europium
Image, source, physical information, and key isotopes.
WebElements: Europium
Extensive information on history, uses, occurrence, compounds, and properties.
Wikipedia: Europium
Properties of the element, including its history, applications, and characteristics.