Britannica micro (sulfur, also spelled sulphur, nonmetallic chemical element belonging to the oxygen family (Group VIa of the periodic table), one of the most reactive of the elements. Known to the ancients (it is referred to in Genesis as brimstone), sulfur was first classified as an element in 1777 by Antoine Lavoisier.) http://id.loc.gov/authorities/subjects/sh85130365

Web. 3 (sulfur or sulphur)

Encarta world Eng. dict. (sulfur, sulphur)

Am. heritage dict. (brimstone: sulfur)

AAT (sulfur UF brimstone)

World book encyc. (sulfur)

MeSH browser, May 30, 2007 (Sulfur. CAS Type 1 name: Sulfur)