Vertex operators for twisted quantum affine algebras

We construct explicitly the $q$-vertex operators (intertwining operators) for the level one modules $V(\Lambda _i)$ of the classical quantum affine algebras of twisted types using interacting bosons, where $i=0, 1$ for $A_{2n-1}^{(2)}$ ($n\geq 3$), $i=0$ for $D_4^{(3)}$, $i=0, n$ for $D_{n+1}^{(2)}$ ($n\geq 2$), and $i=n$ for $A_{2n}^{(2)}$ ($n\geq 1$). A perfect crystal graph for $D_4^{(3)}$ is constructed as a by-product.