A generalized concept of frequency and some applications. - Henning F. Harmuth (IEEE Trans. Inf. Theory, 1968)

Conversion of sequency-limited signals into frequency-limited signals and vice versa (Corresp.). - Henning F. Harmuth; Rudolf de Buda (IEEE Trans. Inf. Theory, 1971)

Two-Dimensional Sequency Filters. - Henning F. Harmuth; Harry C. Andrews; Kosho Shibata (IEEE Trans. Commun., 1972)