Fannes, M. and Nachtergaele, B. and Werner, R. F. (1990) Finitely Correlated States on Quantum Spin Chains. (Preprint)
Fannes, M. and Nachtergaele, B. and Werner, R. F. (1990) Valence Bond States on Quantum Spin Chains as Ground States with Spectral Gap. (Preprint)
Fannes, M. and Nachtergaele, B. and Werner, R. F. (1989) Exact Antiferromagnetic Ground States of Quantum Spin Chains. (Preprint)