1. N.U. Ahmed, Elements of Finite Dimensional Systems and Control Theory. Pitman Monographs and Surveys in Pure and Applied Mathematics (Longman Scientific and Technical, U.K; Copublished by Wiley, London, 1988)
2. N.U. Ahmed, Vector measures for optimal control of impulsive systems in Banach spaces. Nonlinear Funct. Anal. Appl. 5(2), 95–106 (2000)
3. N.U. Ahmed, Some remarks on the dynamics of impulsive systems in Banach spaces. Dyn. Contin. Discrete Impulsive Syst. Ser. A 8, 261–274 (2001)
4. N.U. Ahmed, Systems governed by impulsive differential inclusions on Hilbert spaces. Nonlinear Anal. 45(6), 693–706 (2001)
5. N.U. Ahmed, Necessary conditions of optimality for impulsive systems on Banach spaces. Nonlinear Anal. 51(3), 409–424 (2002)