ChemGlobe: Tungsten
   Electronic, thermal, and steric data along with an isotope table.
   http://partisans.spurious.biz/~pkremer/projects/chemglobe/ptoe/_/74.html

ChemicalElements.com: Tungsten
   Basic information, atomic structure, and isotopes.
   http://www.chemicalelements.com/elements/w.html

ChinaTungsten Online
   Basic properties, compounds, brief history, information about production processes.
   http://chinatungsten.com/chwurl-2-1.htm

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

It's Elemental: Tungsten
   Basic physical and historical information.
   http://education.jlab.org/itselemental/ele074.html

LANL: Tungsten
   Basic information and history.
   http://periodic.lanl.gov/elements/74.html

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

Radiochemistry of Tungsten
   Full text of the monograph by G. W. Leddicotte (Oak Ridge National Laboratory, Oak Ridge, Tennessee). [PDF]
   http://lib-www.lanl.gov/cgi-bin/getfile?rc000011.pdf

USGS Minerals Information: Tungsten
   Statistics and information on the worldwide supply, demand, and flow of the element (PDF format).
   http://minerals.usgs.gov/minerals/pubs/commodity/tungsten/

Visual Elements: Tungsten
   Image, general and physical information, source, uses, key isotopes, and ionisation energies.
   http://www.chemsoc.org/viselements/pages/tungsten.html

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