ChemGlobe: Tungsten: Electronic, thermal, and steric data along with an isotope table.
ChemicalElements.com: Tungsten: Basic information, atomic structure, and isotopes.
ChinaTungsten Online: Basic properties, compounds, brief history, information about production processes.
EnvironmentalChemistry.com: Tungsten: Atomic structure, chemical and physical properties, and table of nuclides.
It's Elemental: Tungsten: Basic physical and historical information.
LANL: Tungsten: Basic information and history.
Lenntech: Tungsten: Physical data, chemical properties, health and environmental effects.
Radiochemistry of Tungsten: Full text of the monograph by G. W. Leddicotte (Oak Ridge National Laboratory, Oak Ridge, Tennessee). [PDF]
Tungsten: Data tables and historic information.
USGS Minerals Information: Tungsten: Statistics and information on the worldwide supply, demand, and flow of the element (PDF format).
Visual Elements: Tungsten: Image, general and physical information, source, uses, key isotopes, and ionisation energies.
WebElements: Tungsten: Extensive information on history, uses, occurrence, compounds, and properties.
Wikipedia: Tungsten: Properties of the element, including its history, applications, and characteristics.