This paper examines the precise correlation between A-bar dependency and the notion of referentiality in Korean. Referentiality is initially defined by the lexical content that only noun phases inherently carry. It is demonstrated that the specification of phi-features renders arguments referential and adjuncts non-referential. This definition is then refined as a set theoretic notion of referentiality to capture the varying degrees of strength in A' dependencies across wh-islands (weak islands) that different wh-phrases show. It is demonstrated that the relative strength of A' dependencies across wh-islands can be predicted by the referential hierarchy. Strong islands are also considered and the notion of "barrier defiability" is introduced to properly constrain A' movements across the strong islands. It is further demonstrated that there may be an argument-adjunct asymmetry even in wh-extractions out of strong islands. If extracted wh-phases are highly referential according to the above referential hierarchy, the barrier may be neutralized and thus an A' dependency may be established even across a strong island. This defiance of a barrier is referred to as Debarrierization as reflected in the relative notion of Barrier Defiability. (Contains 34 references.) (Author/NAV)