REFERENCES
- Ashrafi , N. , Vámos , P. ( 2005 ). On the unit sum number of some rings . Q. J. Math. 56 : 1 – 12 .
- Birkhoff , G. D. ( 1912/13 ). A determinant formula for the number of ways of coloring a map . Ann. of Math. (2) 14 : 42 – 46 .
- Chartrand , G. , Oellermann , O. R. ( 1993 ). Applied and Algorithmic Graph Theory . New York : McGraw-Hill, Inc .
- Corbas , B. , Williams , G. D. ( 2000 ). Rings of order p 5. II. Local rings . J. Algebra 231 : 691 – 704 .
- Dolžan , D. ( 2002 ). Group of units in a finite ring . J. Pure Appl. Algebra 170 : 175 – 183 .
- Goldsmith , B. , Pabst , S. , Scott , A. ( 1998 ). Unit sum numbers of rings and modules . Quart. J. Math. Oxford Ser. (2) 49 : 331 – 344 .
- Grimaldi , R. P. ( 1990 ). Graphs from rings. Proceedings of the 20th Southeastern Conference on Combinatorics, Graph Theory, and Computing (Boca Raton, FL, 1989). Congr. Numer. Vol. 71, pp. 95–103 .
- Henriksen , M. ( 1974 ). Two classes of rings generated by their units . J. Algebra 31 : 182 – 193 .
- Kaplansky , I. ( 1974 ). Commutative Rings . Chicago , Ill.-London : The University of Chicago Press .
- König , D. ( 1916 ). Über Graphen und ihre Anwendung auf Determinantentheorie und Mengenlehre . Math. Ann. 77 : 453 – 465 .
- König , D. ( 1990 ). Theory of Finite and Infinite Graphs . Translated from the German by R. McCoart . Boston , MA : Birkhäuser Boston, Inc .
- Maimani , H. R. , Salimi , M. , Sattari , A. , Yassemi , S. ( 2008 ). Comaximal graph of commutative rings . J. Algebra 319 : 1801 – 1808 .
- McDonald , B. R. ( 1974 ). Finite Rings with Identity . Pure and Applied Mathematics, Vol. 28 . New York : Marcel Dekker, Inc .
- Nicholson , W. K. ( 1977 ). Lifting idempotents and exchange rings . Trans. Amer. Math. Soc. 229 : 269 – 278 .
- Nicholson , W. K. , Zhou , Y. ( 2004 ). Rings in which elements are uniquely the sum of an idempotent and a unit . Glasg. Math. J. 46 : 227 – 236 .
- Raphael , R. ( 1974 ). Rings which are generated by their units . J. Algebra 28 : 199 – 205 .
- Vámos , P. ( 2005 ). 2-Good rings . Q. J. Math. 56 : 417 – 430 .
- Zelinsky , D. ( 1954 ). Every linear transformation is a sum of nonsingular ones . Proc. Amer. Math. Soc. 5 : 627 – 630 .
- Communicated by R. Wiegand.