Ideal nil-extensions of semigroups with semimodular congruence lattices. L.M. Wang (1993) Semigroup forum
Ideals in transformation semigroups Robert P. Sullivan (1978) Commentationes Mathematicae Universitatis Carolinae
Idempotents and inverses in conventional semigroups Francis E. Masat (1982) Czechoslovak Mathematical Journal
Idempotents and product representations with applications to the semigroup of binary relations. G. Markowsky (1972) Semigroup forum
Inflation of Semigroups Stojan Bogdanović, Svetozar Milić (1987) Publications de l'Institut Mathématique