ON A NEW TYPE OF SOLVING PROCEDURE FOR EULER–POISSON EQUATIONS (RIGID BODY ROTATION OVER THE FIXED POINT) Article Ershkov S.V., Leshchenko D. Acta Mechanica. Springer-Verlag Wien. 2018.
ON A NEW TYPE OF SOLVING PROCEDURE FOR LAPLACE TIDAL EQUATION Article Ershkov S.V., Shamin R.V. Physics of Fluids. Vol. 30. 2018.