1. D. Augustin and M. Knebusch, Quadratic modules in R[[X]], Proc. Amer. Math. Soc., 138 (2010), 75-84.
2. A. J. Engler and A. Prestel, Valued Fields, Springer-Verlag (Berlin, 2005).
3. M. Fujita and M. Kageyama, On finiteness of prime cones over simple ADEsingularities of dimension one, Comm. Algebra, 46 (2018), 3986-3995.
4. L. Fuchs, Partially Ordered Algebraic Systems, Pergamon Press (Oxford and New York, 1963).
5. I. Kaplansky, Infinite Abelian Groups, revised ed., The University of Michigan Press (Ann Arbor, Mich, 1969).