@article {MR1611082,
	title = {Normally ordered inverse semigroups},
	journal = {Semigroup Forum},
	volume = {56},
	number = {3},
	year = {1998},
	pages = {418{\textendash}433},
	issn = {0037-1912},
	doi = {10.1007/PL00005955},
	url = {http://dx.doi.org/10.1007/PL00005955},
	author = {Fernandes, Vitor H.}
}
