Equivalence of the variational matrix product method and the density matrix renormalization group applied to spin chainsJ. Dukelsky, M. A. Martín-Delgado, T. Nishino and G. SierraEurophys. Lett., 43 4 (1998) 457-462DOI: https://doi.org/10.1209/epl/i1998-00381-x