Signal understanding: an artificial intelligence approach to modulation classification. - John E. Whelchel; D. L. McNeill; R. D. Hughes; M. M. Loos (TAI, 1989)

The systolic phase rotation FFT-a new algorithm and parallel processor architecture. - John E. Whelchel; John O'Malley; William J. Rinard; James F. McArthur (ICASSP, 1990)

The multidimensional phase-rotation FFT: a new parallel architecture. - Lang P. Withers Jr.; John E. Whelchel (ICASSP, 1991)