TY  - BOOK
AU  - Petrich,M.
TI  - Rings and semigroups
SN  - 0387067302
PY  - 1974///
CY  - Berlin
PB  - Springer-Verlag
KW  - Semigroups
KW  - Associative rings
N1  - Bibliography : p. 168-174
ER  -