1. R. R. Long, ?Some aspects of the flow of stratified fluids. III. Continuous density gradients,? Tellus,7, 342 (1955).
2. S. A. Makarov and Yu. D. Chashechkin, ?Attached internal waves in a fluid with an exponential density distribution,? Zh. Prikl. Mekh. Tekh. Fiz., No. 6, 47 (1981).
3. J. Boussinesq, Theorie Analytique de la Chaleur, Vol. 2, Gauthier-Villars, Paris (1903).
4. M. J. Lighthill, Waves in Fluids, Cambridge (1978).