1. Relative boundedness and compactness theory for second-order differential operators;Anderson;J. Inequal. Appl.,1997
2. Sufficient conditions for weighted inequalities of sum form;Brown;J. Math. Anal. Appl.,1985
3. The Asymptotic Solution of Linear Differential Systems;Eastham,1989
4. Equivalence, adjoints, and symmetry of quasi-differential expressions with matrix-valued coefficients and polynomials in them;Frentzen;Proc. Roy. Soc. Edinburgh Sect. A,1982
5. Unbounded Linear Operators: Theory and Applications;Goldberg,1985