On the existence of [M, n] group codes for the Gaussian channel with [M, n] odd. - Charles P. Downey; John K. Karlof (IEEE Trans. Inf. Theory, 1977)

Optimal [M, 3] group codes for the Gaussian channel (Corresp.). - Charles P. Downey; John K. Karlof (IEEE Trans. Inf. Theory, 1978)

Group codes for the Gaussian broadcast channel with two receivers. - Charles P. Downey; John K. Karlof (IEEE Trans. Inf. Theory, 1980)

Group codes for the M-receiver Gaussian broadcast channel. - Charles P. Downey; John K. Karlof (IEEE Trans. Inf. Theory, 1983)