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.
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]
WebElements: Tungsten
Extensive information on history, uses, occurrence, compounds, and properties.
Wikipedia: Tungsten
Properties of the element, including its history, applications, and characteristics.