On the design of efficient second and higher degree FIR digital differentiators at the frequency π/(any integer). - Hitendra Shah; S. C. Dutta Roy; Balbir Kumar (Signal Process., 1992)

On the design of FIR digital differentiators which are maximally linear at the frequency π/p, p ∈ {positive integers}. - Balbir Kumar; S. C. Dutta Roy; Hitendra Shah (IEEE Trans. Signal Process., 1992)