Britannica Nobel Prize: Argon
   Overview and basic data.
   http://www.britannica.com/nobel/micro/32_18.html

ChemGlobe: Argon
   Electronic, thermal, and steric data along with basic information.
   http://partisans.spurious.biz/~pkremer/projects/chemglobe/ptoe/_/18.html

ChemicalElements.com: Argon
   Basic information, atomic structure, and table of isotopes.
   http://www.chemicalelements.com/elements/ar.html

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

Especiál Gas Inc.: Argon
   Numeric data, uses, and general information.
   http://www.c-f-c.com/specgas_products/argon.htm

It's Elemental: Argon
   Basic physical and historical information.
   http://education.jlab.org/itselemental/ele018.html

LANL: Argon
   Sources, properties, isotopes, and uses.
   http://periodic.lanl.gov/elements/18.html

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

Visual Elements: Argon
   General and physical information, uses, key isotopes, and ionisation energies.
   http://www.chemsoc.org/viselements/pages/argon.html

Wikipedia: Argon
   Details the properties of the element, including its history, applications, and characteristics.
   http://en.wikipedia.org/wiki/Argon