What is the intuitive meaning of FIR and IIR filters? What is the difference? Why do we prefer FIR over IIR? What is the physical significance? - Quora
IIR vs FIR: Understanding their differences
Reduced-Delay IIR Filters - Rick Lyons
Which IIR filters approximate a Gaussian filter? - Signal Processing Stack Exchange
Infinite Impulse Response (IIR) Digital Low-Pass Filter Design by Butterworth Method - Wolfram Demonstrations Project