Chromomagnetism, flavour symmetry breaking and S-wave tetraquarksF. Buccella, H. Høgaasen, J.-M. Richard and P. SorbaEur. Phys. J. C, 49 3 (2007) 743-754DOI: https://doi.org/10.1140/epjc/s10052-006-0142-1