[3] Petrich, M.:
Some relations on the lattice of varieties of completely regular semigroups. Boll. Unione Mat. Ital., Sez. B, Artic. Ric. Mat., VIII. Ser. 5 (2002), 265-278.
MR 1911191 |
Zbl 1072.20067
[13] Petrich, M., Reilly, N. R.:
Completely Regular Semigroups. Canadian Mathematical Society Series of Monographs and Advanced Texts 23. A Wiley-Interscience Publication. John Wiley & Sons, Chichester (1999).
MR 1684919 |
Zbl 0967.20034