LANL: Sulfur - History, properties, production, and uses.
Lenntech: Sulfur - Physical data, chemical properties, health and environmental effects.
Sulphur versus Sulfur - Some thoughts on the history of the spelling of the name of element 16: 'sulfur' vs 'sulphur'.
USGS Minerals Information: Sulfur - Statistics and information on the worldwide supply, demand, and flow of the element (PDF format).
Visual Elements: Sulfur - Image, general and physical information, source, uses, key isotopes, and ionisation energies.
WebElements: Sulfur - Extensive information on history, uses, occurrence, compounds, and properties of the element.
Wikipedia: Sulfur - Properties of the element, including its history, applications, and characteristics.
Radiochemistry of Sulfur - Full text of the monograph by G. W. Leddicotte (Oak Ridge National Laboratory, Oak Ridge, Tennessee). [PDF] (February, 1962)