A resonant energy-transfer theory is applied to the weak wave-wave interactions of random surface gravity waves and internal gravity waves in a constant Väisälä-frequency (exponential-density) ocean….
Kenyon, Kern E.. 1968. "Wave-wave interactions of surface and internal waves." Journal of Marine Research 26, (3). https://elischolar.library.yale.edu/journal_of_marine_research/1129