ChemGlobe: Copper
- Electronic, thermal, and steric data along with an isotope table.
- http://partisans.spurious.biz/~pkremer/projects/chemglobe/ptoe/_/29.html

LANL: Copper
- History, properties, sources, and uses.
- http://periodic.lanl.gov/elements/29.html

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

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

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

Visual Elements: Copper
- Image, general and physical information, source, uses, key isotopes, and ionisation energies.
- http://www.chemsoc.org/viselements/pages/copper.html

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

It's Elemental: Copper
- Basic physical and historical information.
- http://education.jlab.org/itselemental/ele029.html

Copper
- Properties and applications along with photographs and chemical formulas of occurrences.
- http://nautilus.fis.uc.pt/st2.5/scenes-e/elem/e02900.html

ChemicalElements.com: Copper
- Basic information, atomic structure, and table of isotopes.
- http://www.chemicalelements.com/elements/cu.html

Radiochemistry of Copper
- Full text of the monograph by F. F. Dyer (Oak Ridge National Laboratory, Oak Ridge, Tennessee). [PDF]
- http://lib-www.lanl.gov/cgi-bin/getfile?rc000048.pdf