1. M. G. Krein, ?On minimal decomposition of a functional into positive components,? Dokl. Akad. Nauk SSSR,28, No. 1, 18?22 (1940).
2. F. F. Bonsall, ?Endomorphisms of a partially ordered vector spaces without order unit,? London Math. Soc.,30, No. 2, 144?153 (1955).
3. Y.-Ch. Wong and K.-F. Ng, Partially Ordered Topological Vector Spaces, Clarendon Press, Oxford (1973).
4. M. A. Krasnosel'skii, Positive Solutions of Operator Equations [in Russian], Fizmatgiz, Moscow (1962).
5. B. Z. Vulikh, Introduction to the Theory of Partially Ordered Spaces, Gordan and Breach (1967).