Addendum to ``Integrability of Open Spin Chains with Quantum Algebra   Symmetry''
  We show that the quantum-algebra-invariant open spin chains associated with the affine Lie algebras $A^{(1)}_n$ for $n>1$ are integrable. The argument, which applies to a large class of other quantum-algebra-invariant chains, does not require that the corresponding $R$ matrix have crossing symmetry. 
Luca Mezincescu and Rafael I. Nepomechie