Lenntech: Phosphorus - Physical data, chemical properties, health and environmental effects.
Visual Elements: Phosphorus - Image, general and physical information, source, uses, key isotopes, and ionisation energies.
WebElements: Phosphorus - Extensive information on history, uses, occurrence, compounds, and properties of the element.
Wikipedia: Phosphorus - Properties of the element, including its history, applications, and characteristics.
Radiochemistry of Phosphorus - Full text of the monograph by William T. Mullins and G. W. Leddicote (Oak Ridge National Laboratory, Oak Ridge, Tennessee). [PDF] (March, 1962)