Addition to "Evaluation of three 32-bit CMOS" adders in DCVS logic for self-timed circuits"

Two prior publications are reported that should have been referenced in the above-named article (ibid., vol. 33, no. 4, pp. 604??613, Apr. 1998). One from 1955 the other from 1979. The author notes he was not aware of any previous publications that define the complementary carry signal, N_i.