Extension of PDL and consequence relations. - Slavian Radev (Symposium on Computation Theory, 1984)

Expert Logics. - George Gargov; Slavian Radev (AIMSA, 1986)

Infinitary propositional normal modal logic. - Slavian Radev (Stud Logica, 1987)

Argumentation Systems. - Slavian Radev (Fundam. Informaticae, 1996)