Thulium

ChemGlobe: Thulium - Electronic, thermal, and steric data along with an isotope table.
partisans.spurious.biz/~pkremer/projects/chemglobe/ptoe/_/69.html

ChemicalElements.com: Thulium - Basic information, atomic structure, and isotopes.
www.chemicalelements.com/elements/tm.html

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

It's Elemental: Thulium - Basic physical and historical information.
education.jlab.org/itselemental/ele069.html

LANL: Thulium - Basic information and history.
periodic.lanl.gov/elements/69.html

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

Visual Elements: Thulium - Image, uses, physical information, and ionisation energies.
www.chemsoc.org/viselements/pages/thulium.html

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