Orthogonal Polynomial Solutions of Spectral Type Differential Equations: Magnus' Conjecture. - Kil H. Kwon; Lance L. Littlejohn; Gang J. Yoon (J. Approx. Theory, 2001)

Left-definite theory with applications to orthogonal polynomials. - Andrea Bruder; Lance L. Littlejohn; Davut Tuncer; Richard Wellman (J. Comput. Appl. Math., 2010)

The Legendre-Stirling numbers. - George E. Andrews; Wolfgang Gawronski; Lance L. Littlejohn (Discret. Math., 2011)

The Jacobi-Stirling numbers. - George E. Andrews; Eric S. Egge; Wolfgang Gawronski; Lance L. Littlejohn (J. Comb. Theory A, 2013)

Factorization of second-order linear differential equations and Liouville-Neumann expansions. - Esther García; Lance L. Littlejohn; José L. López 001; Ester Pérez Sinusía (Math. Comput. Model., 2013)

On the asymptotic normality of the Legendre-Stirling numbers of the second kind. - Wolfgang Gawronski; Lance L. Littlejohn; Thorsten Neuschel (Eur. J. Comb., 2015)

The spectral analysis of three families of exceptional Laguerre polynomials. - Constanze Liaw; Lance L. Littlejohn; Robert Milson; Jessica Stewart (J. Approx. Theory, 2016)

Differential operator for discrete Gegenbauer-Sobolev orthogonal polynomials: Eigenvalues and asymptotics. - Lance L. Littlejohn; Juan F. Mañas-Mañas; Juan J. Moreno-Balcázar; Richard Wellman (J. Approx. Theory, 2018)