1. The SLEIGN2 Sturm–Liouville code, ACM TOMS;Bailey;ACM Trans. Math. Software,2001
2. Boundary Value Problems and Symplectic Algebra for Ordinary Differential and Quasi-Differential Operators;Everitt,1999
3. On the positive square root of the fourth derivative operator;Russell;Quart. Appl. Math.,1988
4. The classification of self-adjoint boundary conditions: Separated, coupled, and mixed;Wang;J. Funct. Anal.,2008
5. Sturm–Liouville Theory;Zettl,2005