Numerically constructible observers for linear time-varying descriptor systems. - Neil Biehn; Stephen L. Campbell; Ramine Nikoukhah; François Delebecque (Autom., 2001)

Convergence of Nonconvergent IRK Discretizations of Optimal Control Problems with State Inequality Constraints. - John T. Betts; Neil Biehn; Stephen L. Campbell (SIAM J. Sci. Comput., 2002)