by White, P.A., Calhoun, M.D., Kuhnle, P.F.
Published in IEEE Proceedings on Southeastcon (1990)

by Hamell, R.L., Kuhnle, P.F., Sydnor, R.L., Dick, G.J., Kirk, A., Diener, W.A.
Published in Proceedings of the 1992 IEEE Frequency Control Symposium (1992)