REFERENCES
- Fountain , J. , Petrich , M. ( 1996 ). Orders in normal bands of groups . Mathematika 43 : 295 – 319 .
- Pastijn , F. ( 1990 ). The lattice of completely regular semigroup varieties . J. Austral. Math. Soc. Ser. A 49 : 24 – 42 .
- Pastijn , F. , Yan , X. (1994). Varieties of semigroups and varieties of completely regular semigroups closed for certain extensions. J. Algebra 163:777–794.
- Petrich , M. ( 1987 ). A structure theorem for completely regular semigroups . Proc. Amer. Math. Soc. 99 : 617 – 622 .
- Petrich , M. ( 2007 ). Canonical varieties of completely regular semigroups . J. Aust. Math. Soc. 83 : 87 – 104 .
- Petrich , M. ( 2014 ). A lattice of varieties of completely regular semigroups . Comm. Algebra 42 : 1397 – 1413 .
- Petrich , M. , Reilly , N. R. ( 1990 ). Operators related to E-disjunctive and fundamental completely regular semigroups . J. Algebra 134 : 1 – 27 .
- Petrich , M. , Reilly , N. R. ( 1990 ). Operators related to idempotent generated and monoid completely regular semigroups . J. Aust. Math. Soc. Ser. A 49 : 1 – 23 .
- Petrich , M. , Reilly , N. R. ( 1999 ). Completely Regular Semigroups . New York : Wiley .
- Polák , L. ( 1985 ). On varieties of completely regular semigroups I . Semigroup Forum 32 : 97 – 123 .
- Polák , L. ( 1987 ). On varieties of completely regular semigroups II . Semigroup Forum 36 : 253 – 284 .
- Song , G. , Liu , G. , Zhang , J. ( 2004 ). A construction of regular cryptogroups . Semigroup Forum 69 : 409 – 422 .
- Song , G. , Meng , X. , Liu , G. ( 2006 ). On the structure of cryptogroups . Semigroup Forum 73 : 395 – 403 .
- Communicated by V. Gould.