@article{article030f2295,
title   = {Multi-step transformation in numerical renormalization group},
author = {Ferreira, Joao Vitor Batista and Líbero, Valter Luiz and Oliveira, Luiz Nunes de},
year = {2006},
doi = {10.1016/j.cpc.2005.12.022},
journal   = {Computer Physics Communications}
}