Phosphorus

ChemGlobe: Phosphorus - Electronic, thermal, and steric data along with basic information.
partisans.spurious.biz/~pkremer/projects/chemglobe/ptoe/_/15.html

ChemicalElements.com: Phosphorus - Basic information, atomic structure, and table of isotopes.
www.chemicalelements.com/elements/p.html

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

It's Elemental: Phosphorus - Basic physical and historical information.
education.jlab.org/itselemental/ele015.html

LANL: Phosphorus - Properties, handling, production, and uses.
periodic.lanl.gov/elements/15.html

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

Visual Elements: Phosphorus - Image, general and physical information, source, uses, key isotopes, and ionisation energies.
www.chemsoc.org/viselements/pages/phosphorus.html

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

Radiochemistry of Phosphorus - Full text of the monograph by William T. Mullins and G. W. Leddicote (Oak Ridge National Laboratory, Oak Ridge, Tennessee). [PDF] <small>(March, 1962)</small>
lib-www.lanl.gov/cgi-bin/getfile=3frc000024.pdf