  Drinfeld realisations are constructed for the quantum affine superalgebras of
the series ${\rm\mathfrak{osp}}(1|2n)^{(1)}$,${\rm\mathfrak{sl}}(1|2n)^{(2)}$
and ${\rm\mathfrak{osp}}(2|2n)^{(2)}$. By using the realisations, we develop
vertex operator representations and classify the finite dimensional irreducible
representations for these quantum affine superalgebras.
