  Recent investigations address transport through ballistic charge-neutral
graphene strips coupled to doped graphitic leads. This paper shows that
identical transport properties arise when the leads are replaced by quantum
wires. This duality between graphitic and metallic leads originates in the
selection of modes with transverse momentum close to the K points, and can be
extended to a wide class of contact models. Among this class we identify a
simple, effective contact model, which provides an efficient tool to study the
transport through extended weakly-doped graphitic systems.
