1. E. Becker: ?Hereditarily pythagorean fields and orderings of higher levels?, I.M.P.A., Lecture Notes # 29 (1978), Rio de Janeiro
2. E. Becker: ?Summen n-ter Potenzen in K�rpern?, J. reine angew. Math. 307/308 (1979), 8?30
3. E. Becker: ?Extended Artin-Schreier theory of fields?, Rocky Mountain J. of Math., vol. 14, # 4, Fall 1984
4. E. Becker, J. Harman and A. Rosenberg: ?Signatures of fields and extension theory?, J. reine angew. Math. 330 (1982), 53?75
5. E. Becker and B. Jacob: ?Rational points on algebraic varieties over a generalized real closed field: a model theoretic approach?, J. reine angew. Math. 357 (1985), 77?95