J. Calvert

Some generalizations of Opial’s inequality

J. Calvert, 1967 .

An integral inequality with applications to the Dirichlet problem

J. Calvert, 1967 .

Energy bounds and virial theorems for abstract wave equations

L. Bobisud, J. Calvert, 1973 .

Some existence results for singular boundary value problems

L. Bobisud, W. D. Royalty, L. E Bobisud, 1993, Differential and Integral Equations.