Holmium

ChemGlobe: Holmium - Electronic, thermal, and steric data along with an isotope table.
partisans.spurious.biz/~pkremer/projects/chemglobe/ptoe/_/67.html

ChemicalElements.com: Holmium - Basic information, atomic structure, and isotopes table.
www.chemicalelements.com/elements/ho.html

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

It's Elemental: Holmium - Basic physical and historical information.
education.jlab.org/itselemental/ele067.html

LANL: Holmium - Basic information, history, and properties.
periodic.lanl.gov/elements/67.html

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

Visual Elements: Holmium - Image, source, uses, key isotopes, and ionisation energies.
www.chemsoc.org/viselements/pages/holmium.html

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