@article{GDZPPN001256432,
title = {Monoids on the 2-disk.},
journal = {Semigroup forum},
volume = {30},
year = {1984},
pages = {83-92},
zbl = {0531.22001},
url = {http://dml.mathdoc.fr/item/GDZPPN001256432}
}
Castellano, B.M. Monoids on the 2-disk.. Semigroup forum, Tome 30 (1984) pp. 83-92. http://gdmltest.u-ga.fr/item/GDZPPN001256432/