Bound states of topological defects in parametrically excited capillary wavesV. O. Afenchenko, A. B. Ezersky, S. V. Kiyashko and A. V. NazarovskyEur. Phys. J. Special Topics, 146 (2007) 99-110DOI: https://doi.org/10.1140/epjst/e2007-00172-1