ChemGlobe: Seaborgium: Electronic data and isotope table.
ChemicalElements: Seaborgium: Basic information.
EnvironmentalChemistry.com: Seaborgium: Atomic structure and table of nuclides.
It's Elemental: Seaborgium: Basic physical and historical information.
LANL: Seaborgium: Basic information and history.
Lenntech: Seaborgium: Physical data and chemical properties.
Seaborgium: Historic information.
Visual Elements: Seaborgium: Physical information, ionisation energies, and key isotopes.
WebElements: Seaborgium: Information on history, isolation, and properties.
Wikipedia: Seaborgium: History and basic information on the element.