ChemGlobe: Sulfur
- Electronic, thermal, and steric data along with basic information.
- http://partisans.spurious.biz/~pkremer/projects/chemglobe/ptoe/_/16.html

LANL: Sulfur
- History, properties, production, and uses.
- http://periodic.lanl.gov/elements/16.html

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

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

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

Sulphur versus Sulfur
- Some thoughts on the history of the spelling of the name of element 16: 'sulfur' vs 'sulphur'.
- http://www.quinion.com/words/topicalwords/tw-sul1.htm

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

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

ChemicalElements.com: Sulfur
- Basic information, atomic structure, and table of isotopes.
- http://www.chemicalelements.com/elements/s.html

It's Elemental: Sulfur
- Basic physical and historical information.
- http://education.jlab.org/itselemental/ele016.html

Radiochemistry of Sulfur
- 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?rc000050.pdf