@article{1077309880,
author = {Butler, Kim Ki-Hang and Krabill, James Richard},
title = {Abelian subsemigroups, enumeration, and universal matrices},
journal = {Duke Math. J.},
volume = {40},
number = {1},
year = {1973},
pages = { 587-598},
language = {en},
url = {http://dml.mathdoc.fr/item/1077309880}
}
Butler, Kim Ki-Hang; Krabill, James Richard. Abelian subsemigroups, enumeration, and universal matrices. Duke Math. J., Tome 40 (1973) no. 1, pp. 587-598. http://gdmltest.u-ga.fr/item/1077309880/