On optimal signal sets for digital communications with finite precision and amplitude constraints. - Michael L. Honig; Stephen P. Boyd; B. Gopinath; Erik Rantapaa (IEEE Trans. Commun., 1991)

Discrete-time signal design for maximizing separation in amplitude. - Michael L. Honig; Kenneth Steiglitz; Venkataramanan Balakrishnan; Erik Rantapaa (IEEE Trans. Inf. Theory, 1995)