“…The problem has been studied in [24] and model equations both for long and short waves are derived from the governing equations as well. The short-wave effects usually compete with the capillarity effects and then resonances can be observed -these have been studied quite a lot, see for example [6,9,13,17,19,23,25,30]. For the intermediate long waves or for waves on deep water the so-called Benjamin-Ono (BO) [1,7,29] and the Intermediate Long Wave Equation (ILWE) [14,18,21] are derived for the internal waves below a flat surface, which leads to some simplifications and these models are in fact integrable.…”