Below are some technical papers that will hopefully contribute some knowledge and algorithms to the DSP community in general. This knowledge is placed in the public domain.
Linear trapezoidal integrated filters
OnePoleLinearLowPass.pdf – One Pole Low Pass Filter
SvfLinearTrapOptimised2.pdf – State Variable Filter
SkfLinearTrapOptimised2.pdf – Sallen Key Low Pass Filter
SVF-vs-DF1.pdf – Noise performance plots
SvfLinearTrapAllOutputs.pdf – State Variable Filter Simultaneous computation of all outputs