Rubidium

ChemGlobe: Rubidium - Electronic, thermal, and steric data along with an isotope table.
partisans.spurious.biz/~pkremer/projects/chemglobe/ptoe/_/37.html

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

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

It's Elemental: Rubidium - Basic physical and historical information.
education.jlab.org/itselemental/ele037.html

LANL: Rubidium - Sources, properties, isotopes, and uses.
periodic.lanl.gov/elements/37.html

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

Visual Elements: Rubidium - Image, source, uses, physical information, and key isotopes.
www.chemsoc.org/viselements/pages/rubidium.html

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

Radiochemistry of Rubidium - Full text of the monograph by G. W. Leddicotte (Oak Ridge National Laboratory, Oak Ridge, Tennessee). [PDF] <small>(February, 1962)</small>
lib-www.lanl.gov/cgi-bin/getfile=3frc000003.pdf