Oliveira, R.; Terhal, B.M. The complexity of quantum spin systems on a two-dimensional square lattice. Quantum Information & Computation. 2008-11-01, 8: 0900–0924. Bibcode:2005quant.ph..4050O. arXiv:quant-ph/0504050.
Oliveira, R.; Terhal, B.M. The complexity of quantum spin systems on a two-dimensional square lattice. Quantum Information & Computation. 2008-11-01, 8: 0900–0924. Bibcode:2005quant.ph..4050O. arXiv:quant-ph/0504050.