ChemGlobe: Antimony - Electronic, thermal, and steric data along with an isotope table. - http://partisans.spurious.biz/~pkremer/projects/chemglobe/ptoe/_/51.html
LANL: Antimony - History, sources, properties, and uses. - http://periodic.lanl.gov/elements/51.html
Wikipedia: Antimony - Details the properties of the element, including its history, applications, and characteristics. - http://en.wikipedia.org/wiki/Antimony
Lenntech: Antimony - Physical data, chemical properties, health and environmental effects. - http://www.lenntech.com/Periodic-chart-elements/Sb-en.htm
EnvironmentalChemistry.com: Antimony - Atomic structure, properties, and table of nuclides. - http://environmentalchemistry.com/yogi/periodic/Sb.html
ChemicalElements.com: Antimony - Basic information, atomic structure, and table of isotopes. - http://www.chemicalelements.com/elements/sb.html
USGS Minerals Information: Antimony - Overview and a number of publications in PDF format. - http://minerals.usgs.gov/minerals/pubs/commodity/antimony/
Radiochemistry of Antimony - Full text of the monograph by William J. Maeck (Phillips Petroleum Company, Atomic Energy Division, Idaho Falls, Idaho). [PDF] - http://lib-www.lanl.gov/cgi-bin/getfile?rc000057.pdf
Visual Elements: Antimony - Image, source, uses, general and physical information, and key isotopes. - http://www.chemsoc.org/viselements/pages/antimony.html