R. J. Knill,N. S. F. -C. B. M. S. Reigional conference on Harmonic maps.N. S. F. -C. B. M. S. Regional conference on Harmonic maps (1980 : Tulane Univ.):Harmonic maps; proceedings.Springer,1982.
M. S. Hussein,International Nuclear Physics Conference.International Nuclear Physics Conference (1989 : Brasil):proceedings of the .V.2,Invited papers.World Scientific,1990.