1. Lattice Theory;Birkhoff,1940
2. Operator and differential equations in ordered spaces;Carl;J. Math. Anal. Appl.,1999
3. Nonlinear Differential Equations in Ordered Spaces;Carl,2000
4. Elliptic problems with lack of compactness via a new fixed point theorem;Carl;J. Differential Equations,2002
5. Existence results for equations in ordered Hilbert spaces and elliptic BVP's;Carl;Nonlinear Funct. Anal. Appl.,2002