Gallium

It's Elemental: Gallium - Basic physical and historical information.
http://education.jlab.org/itselemental/ele031.html

Visual Elements: Gallium - General and physical information, key isotopes, and ionisation energies.
http://www.chemsoc.org/viselements/pages/gallium.html

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

WebElements: Gallium - Extensive information on history, uses, occurrence, compounds, and properties of the element.
http://www.webelements.com/gallium/

Discovery of Gallium - Article by P.E. Lecoq de Boisbaudran.
http://dbhs.wvusd.k12.ca.us/webdocs/Chem-History/Disc-of-Gallium.html

ChemGlobe: Gallium - Electronic, thermal, and steric data along with an isotope table.
http://partisans.spurious.biz/~pkremer/projects/chemglobe/ptoe/_/31.html

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

LANL: Gallium - Sources, properties, uses, and costs.
http://periodic.lanl.gov/elements/31.html

USGS Minerals Information: Gallium - Statistics and information on the worldwide supply, demand, and flow of the element. [PDF]
http://minerals.usgs.gov/minerals/pubs/commodity/gallium/

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

ChemicalElements.com: Gallium - Basic information, atomic structure, and isotopes.
http://www.chemicalelements.com/elements/ga.html