LANL: Iodine: - History, sources, uses, properties, and isotopes.
Lenntech: Iodine: - Physical data, chemical properties, health and environmental effects.
USGS Minerals Information: Iodine: - Statistics and information on the worldwide supply, demand, and flow of the element (PDF format).
Visual Elements: Iodine: - General and physical information, source, uses, biological role, key isotopes, and ionisation energies.
Wikipedia: Iodine: - Properties of the element, including its history, applications, and characteristics.
Radiochemistry of Iodine: - Full text of the monograph by Jacob Kleinberg (University of California, Los Alamos Scientific Laboratory, Los Alamos, New Mexico and University of Kansas, Lawrence, Kansas). [PDF] (September, 1977)