Algorithm 810: The SLEIGN2 Sturm-Liouville Code. - Paul B. Bailey; W. Norrie Everitt; Anton Zettl (ACM Trans. Math. Softw., 2001)

Fourier-Bessel-type series: The fourth-order case. - W. Norrie Everitt; Clemens Markett (J. Approx. Theory, 2009)