Lowest-lying tetra-quark hadrons in anisotropic lattice QCD Mushtaq Loan, Zhi-Huan Luo and Yu Yiu Lam Eur. Phys. J. C, 57 3 (2008) 579-587 Published online: 22 August 2008 DOI: 10.1140/epjc/s10052-008-0689-0