REFERENCES
- Albert , A. A. ( 1940 ). On ordered algebras . Bull. Amer. Math. Soc. 46 : 521 – 522 . [CSA]
- Becker , E. ( 1979 ). Summen n-ter Potenzen in Körpern . J. Reine Angew. Math. 307/308 : 8 – 30 . [CSA]
- Becker , E. , Canales , M. ( 1999 ). Higher levels of Z/p l Z and period equations . Manuscripta Math. 99 ( 4 ): 425 – 441 . [CSA] [CROSSREF]
- Cimpric , J. ( 2001 ). Higher product levels of noncommutative rings . Comm. Algebra 29 ( 1 ): 193 – 200 . [CSA] [CROSSREF]
- Cimpric , J. ( 2004 ). Valuation theory of higher level *-orderings . J. Pure Appl. Algebra 194 ( 3 ): 239 – 262 . [CSA] [CROSSREF]
- Cimpric , J. , Veluscek , D. ( 2005 ). Higher product levels of domains . J. Pure Appl. Algebra. 198 ( 1–3 ): 67 – 74 . [CSA] [CROSSREF]
- Craven , T. ( 1982 ). Witt rings and orderings of skew fields . J. Algebra 77 ( 1 ): 74 – 96 . [CSA] [CROSSREF]
- Craven , T. (1992). Witt groups of Hermitian forms over *-fields. J. Algebra 147(1):96–127. [CSA] [CROSSREF]
- Joly , J.-P . ( 1970 ). Sommes de puissances d-ièmes dans un anneau commutatif . Acta Arith. 17 : 37 – 114 . [CSA]
- Klep , I. , Veluscek , D. ( 2004 ). n-real valuations and the higher level version of the Krull-Baer theorem . J. Algebra 279 ( 1 ): 345 – 361 . [CSA] [CROSSREF]
- Lam , T. Y. ( 2001 ). A First Course in Noncommutative Rings , 2nd ed. . Graduate Texts in Mathematics . 131 . New York : Springer-Verlag , pp. xx+385 . ISBN: 0-387-95183-0.
- Leep , D. B. , Tignol , J.-P. , Vast , N. ( 1989 ). The level of division algebras over local and global fields . J. Number Theory 33 ( 1 ): 53 – 70 . [CSA] [CROSSREF]
- Lewis , D. W. ( 1999 ). Levels of fields and quaternion algebras—a survey . Théorie Des Nombres Années 1996/97–1997/98 . Besançon: Publ. Math. UFR Sci. Tech. Besançon : Univ. Franche-Comté , p. 9 .
- Pfister , A. ( 1995 ). Quadratic Forms with Applications to Algebraic Geometry and Topology. London Mathematical Society Lecture Note Series. 217 . Cambridge : Cambridge University Press . pp. viii+179 . ISBN: 0-521-46755-1.
- Powers , V. ( 1991 ). Holomorphy rings and higher level orders on skew fields . J. Algebra 136 ( 1 ): 51 – 59 . [CSA] [CROSSREF]
- Scharlau , W. , Tschimmel , A. ( 1983 ). On the level of skew-fields . Arch. Math. (Basel) 40 ( 4 ): 314 – 315 . [CSA] [CROSSREF]
- Szele , T. ( 1952 ). On ordered skew fields . Proc. Amer. Math. Soc. 3 : 410 – 413 . [CSA]
- Wadsworth , A. R. ( 1990 ). In a division algebra of even degree −1 is a product of squares . Bull. Soc. Math. Belg. Sér. B 42 ( 1 ): 103 – 104 . [CSA]
- Communicated by R. Parimala.