Recent Developments in Sturm-Liouville Theory

by Zettl, Anton
Published 2021

Norm Inequalities for Derivatives and Differences

by Kwong, Man K., Zettl, Anton
Published 1992

The Deficiency Index Problem for Powers of Ordinary Differential Expressions

by Kauffman, Robert M., Read, Thomas T., Zettl, Anton
Published 1977