Density-matrix renormalization group study of the spin-Peierls instability in the antiferromagnetic Heisenberg ladderY.J. Xu, H. Zhao, Y.G. Chen and Y.H. YanEur. Phys. J. B, 85 12 (2012) 393DOI: https://doi.org/10.1140/epjb/e2012-30316-7