Thulium

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

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

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

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

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

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

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

WebElements: Thulium
Extensive information on history, uses, occurrence, compounds, and properties.
http://www.webelements.com/webelements/elements/text/Tm/key.html

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