See also:

• Science: Chemistry: Elements: Lanthanides  (2)

ChemGlobe: Thulium: - Electronic, thermal, and steric data along with an isotope table.

ChemicalElements.com: Thulium: - Basic information, atomic structure, and isotopes.

EnvironmentalChemistry.com: Thulium: - Atomic structure, chemical and physical properties, and table of nuclides.

It's Elemental: Thulium: - Basic physical and historical information.

LANL: Thulium: - Basic information and history.

Lenntech: Thulium: - Physical data, chemical properties, health and environmental effects.

Visual Elements: Thulium: - Image, uses, physical information, and ionisation energies.

Wikipedia: Thulium: - Properties of the element, including its history, applications, and characteristics.