1. Extensions and covers for semigroups whose idempotents form a left regular band;Branco;Semigroup Forum,2010
2. Stable meet semilattice fibrations and free restriction categories;Cockett;Theor. Appl. Comput. Sci.,2006
3. Restriction categories I: categories of partial maps;Cockett;Theoret. Comput. Sci.,2002
4. C. Cornock, Restriction semigroups: structure, varieties and presentations, Ph.D. Thesis, University of York, 2011.
5. Right PP monoids with central idempotents;Fountain;Semigroup Forum,1977