1. [AO] D. F. Anderson and J. Ohm, Valuations and semi-valuations of graded domains, Math. Ann. 256(1981), 145–156.
2. [B] G. Brumfiel, Partially Ordered Rings and Semi-Algebraic Geometry. London Math. Soc. Lecture Note Series 37, Cambridge, 1979.
3. [BKW] Bigard, Keimel and Wolfenstein, Groupes et anneaux reticulés, Lecture Notes in Mathematics 608. Springer-Verlag, Berlin, 1971.
4. [BP] G. Birkhoff and R. Pierce, Lattice ordered rings, Anais Acad. Bras. Ci. 28 (1956), 41–69.
5. [DM] C. N. Delzell and J. Madden, Lattice-ordered rings and semialgebraic geometry: I, Real analytic and Algebraic Geometry. Proc. Intenat. Conf., Trento, Italy, September 21–25, 1992, F. Broglia , M. Galbiati, A. Tognoli, eds., Walter de Gruyter (1995), 103–29.