We develop virial theorems for ordinary differential equations. Both the Finkelstein and Fock methods are used. Vanishing of boundary conditions at singular points are handled by asymptotic methods as well as conditions which guarantee that the singular point is both a strong limit point and Dirichlet. Applications are given to determine intervals which contain no eigenvalues.
"The virial theorem for higher-order differential operators." Differential Integral Equations 25 (9/10) 915 - 937, September/October 2012. https://doi.org/10.57262/die/1356012375