ChemGlobe: Strontium
- Electronic, thermal, and steric data along with an isotope table.
- http://partisans.spurious.biz/~pkremer/projects/chemglobe/ptoe/_/38.html

LANL: Strontium
- History, forms, properties, isotopes, and uses.
- http://periodic.lanl.gov/elements/38.html

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

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

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

USGS Minerals Information: Strontium
- Statistics and information on the worldwide supply, demand, and flow of the element (PDF format).
- http://minerals.usgs.gov/minerals/pubs/commodity/strontium/

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

It's Elemental: Strontium
- Basic physical and historical information.
- http://education.jlab.org/itselemental/ele038.html

Visual Elements: Strontium
- Uses, physical information, key isotopes, and ionisation energies.
- http://www.chemsoc.org/viselements/pages/strontium.html