On stability of nonlinear systems of ordinary differential equations. - M. M. A. El-Sheikh; A. A. Soliman; M. H. Abdalla (Appl. Math. Comput., 2000)

On stability of nonlinear differential systems via cone-valued Liapunov function method. - M. M. A. El-Sheikh; A. A. Soliman; M. H. Abdalla (Appl. Math. Comput., 2001)

Integral stability criteria of nonlinear differential systems. - A. A. Soliman; M. H. Abdalla (Math. Comput. Model., 2008)