A universal algebra approach to free projective planes. (Short Communication). Ki Hang Kim; Fred W. Roush — 1978 Aequationes mathematicae
A universal algebra approach to free projective planes. Ki Hang Kim; Fred W. Roush — 1979 Aequationes mathematicae
The semigroup of circulant Boolean matrices Kim Ki-Hang Butler; Štefan Schwarz — 1976 Czechoslovak Mathematical Journal
Circulant Boolean relation matrices Kim Ki-Hang Butler; James Richard Krabill — 1974 Czechoslovak Mathematical Journal