Wolfram Demonstrations Projecthttp://demonstrations.wolfram.com/An Open Resource of Interactive Mathematica VisualizationsCopyright 2009 Wolfram Demonstrations Project & ContributorsHelium Ionization Fraction as Function of Density and Temperaturehttp://demonstrations.wolfram.com/HeliumIonizationFractionAsFunctionOfDensityAndTemperature/]]>http://demonstrations.wolfram.com/HeliumIonizationFractionAsFunctionOfDensityAndTemperature/Binary Inspiral Gravitational Waves from a Post-Newtonian Expansionhttp://demonstrations.wolfram.com/BinaryInspiralGravitationalWavesFromAPostNewtonianExpansion/]]>http://demonstrations.wolfram.com/BinaryInspiralGravitationalWavesFromAPostNewtonianExpansion/