1. Widnall, S. E. , Bliss, D. & Zalay, A. 1970 Theoretical and experimental study of the stability of a vortex pair. Proceedings of the Symposium on Aircraft Wake Turbulence , Seattle, Washington.
2. Milne-Thompson, L. M. 1968 Theoretical Hydrodynamics .Macmillan.
3. Thomson, W. 1910b The translatory velocity of a circular vortex ring. Mathematical and Phyaical Papers , vol. IV.Cambridge University Press.
4. Bergman, K. H. 1969 On the dynaniio stability of convective atmospheric vortices. Ph.D. thesis, Department of Atmospheric Sciences,University of Washington.
5. Thomson, W. 1910a Vibrations of a columnar vortex. Mathematical and Physical Papers , vol. IV.Cambridge University Press.