1
Published 1972
Springer Berlin Heidelberg
Table of Contents: ... of formally selfadjoint ordinary differential operators -- Recent results in the theory of variational...

2
Published 1981
Springer Berlin Heidelberg
Table of Contents: ... on second order criteria for maxima and minima -- Variational methods and almost solvability of semilinear...

3
Published 1982
Springer Berlin Heidelberg
Table of Contents: ... variational inequalities -- A further result on the essential spectrum of linear 2nth order differential...