A Delay Line and Logic Circuits Utilizing Charge-Storage Subharmonic Parametric Oscillators. - Robert H. Mitchell; Thomas Williams; William D. Ryan (IEEE Trans. Computers, 1968)

Implementation of a transient macro-model in large logic systems. - N. B. Rabbat; William D. Ryan (AFIPS Spring Joint Computing Conference, 1972)

Improved Simulation of Pulse Propagation Between Digital Circuits. - N. B. Rabbat; S. Q. A. M. A. Hossain; William D. Ryan (IEEE Trans. Computers, 1976)