ChemGlobe: Indium
- Electronic, thermal, and steric data along with an isotope table.
- http://partisans.spurious.biz/~pkremer/projects/chemglobe/ptoe/_/49.html

LANL: Indium
- History, sources, properties, and uses.
- http://periodic.lanl.gov/elements/49.html

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

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

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

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

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

It's Elemental: Indium
- Basic physical and historical information.
- http://education.jlab.org/itselemental/ele049.html

Radiochemistry of Indium
- Full text of the monograph by Duane Neuman Sunderman (Battelle Memorial Institute, Columbus, Ohio) and Charles William Townley (Battelle Memorial Institute, Columbus, Ohio). [PDF]
- http://lib-www.lanl.gov/cgi-bin/getfile?rc000020.pdf

Visual Elements: Indium
- Image, appearance, uses, physical information, and ionisation energies.
- http://www.chemsoc.org/viselements/pages/indium.html