1. C. S. Yih, Stratified Flows (Acad. Press, N. Y., 1980).
2. P. H. Le Blond and L. A. Mysak, Waves in the Ocean (Elsevier Scientific Publishing Company, 1978).
3. L. V. Ovsyannikov, N. I. Makarenko, V. I. Nalimov, et al., Nonlinear Problems in the Theory of Surface and Internal Waves (Nauka. Sibirskoe Otdelenie, Novosibirsk, 1985) [in Russian].
4. L. V. Ovsyannikov, “Second Approximation in the Shallow Water Theory," Izv. Akad. Nauk SSSR. Mekhanika Zhidkosti i Gaza, No. 2, 175 (1980).
5. M. Miyata, “An Internal Solitary Wave of Large Amplitude," La Mer 23 (2), 43–48 (1985).