2004, THEORETICAL COMPUTER SCIENCE, Bellantoni,S;Oitavem,I

2004, ALGEBRA COLLOQUIUM, Blyth,TS;Silva,HJ

2004, INTERNATIONAL JOURNAL OF ALGEBRA AND COMPUTATION, Delgado,M;Fernandes,VH;Margolis,S;Steinberg,B

2005, GLASGOW MATHEMATICAL JOURNAL, Fernandes,VH;Gomes,GMS;Jesus,MM

2005, INTERNATIONAL JOURNAL OF ALGEBRA AND COMPUTATION, Malheiro,A

2005, SEMIGROUP FORUM, Araujo,J;Konieczny,J

2005, COMMUNICATIONS IN ALGEBRA, Fernandes,VH;Gomes,GMS;Jesus,MM

2005, COMMUNICATIONS IN ALGEBRA, Araujo,J;Fountain,J

2005, COMMUNICATIONS IN ALGEBRA, Andre,JM

2005, ANNALS OF PURE AND APPLIED LOGIC, Buchholz,W;Kahle,R