Regular boundary value problems associated with pairs of ordinary differential expressions

Selfadjoint extensions of M0.- Forms generated by selfadjoint extensions of M0.- Hilbert spaces generated by positive selfadjoint extensions of Mo.- Minimal and maximal subspaces for the pair L,M.- Intermediate subspaces.- Spectra and eigenvalues.- Resolvents.- Eigenfunction expansions for selfadjoint subspaces.- Semibounded intermediate subspaces.- Some special cases.