Visual Elements: Technetium - Image, general and physical information, source, uses, key isotopes, and ionisation energies.
WebElements: Technetium - Extensive information on history, uses, occurrence, compounds, and properties.
Wikipedia: Technetium - Properties of the element, including its history, applications, and characteristics.
Radiochemistry of Technetium - Full text of the monograph by Edward Anders (Enrico Fermi Institute and Dept. of Chemistry, University of Chicago, Chicago, Illinois). [PDF] (November, 1960)