Limiting set of second order spectra. - Lyonell Boulton (Math. Comput., 2006)

On pseudospectra of matrix polynomials and their boundaries. - Lyonell Boulton; Peter Lancaster; Panayiotis J. Psarrakos (Math. Comput., 2008)

Non-variational computation of the eigenstates of Dirac operators with radially symmetric potentials. - Lyonell Boulton; Nabile Boussaid (LMS J. Comput. Math., 2010)

Schur Decompositions of a Matrix and the Boundary of Its Pseudospectrum. - Lyonell Boulton; Peter Lancaster (SIAM J. Matrix Anal. Appl., 2010)

Finite Element Eigenvalue Enclosures for the Maxwell Operator. - Gabriel R. Barrenechea; Lyonell Boulton; Nabile Boussaid (SIAM J. Sci. Comput., 2014)

Local two-sided bounds for eigenvalues of self-adjoint operators. - Gabriel R. Barrenechea; Lyonell Boulton; Nabile Boussaid (Numerische Mathematik, 2017)