Observation of two-magnon bound states in the spin-1 anisotropic Heisenberg antiferromagnetic chain system 'NiCl IND.2´-4SC('NH IND.2´) IND.2 - Zvyagin, S A; Batista, C D; Krzystek, J; Zapf, V S; Jaime, M; Paduan-Filho, Armando; Wosnitza, J (Physica B-Condensed Matter, 2008)