1. Introduction to Commutative Algebra;Atiyah,1969
2. Hereditarily Pythagorean Fields and Orderings of Higher Level;Becker,1978
3. Summen n-ter Potenzen in Körpern;Becker;J. Reine Angew. Math.,1979
4. Extended Artin–Schreier theory of fields;Becker;Rocky Mountain J. Math.,1984
5. Signatures of fields and extension theory;Becker;J. Reine Angew. Math.,1982