@article {MR2417624,
	title = {Normally ordered semigroups},
	journal = {Glasg. Math. J.},
	volume = {50},
	number = {2},
	year = {2008},
	pages = {325{\textendash}333},
	issn = {0017-0895},
	doi = {10.1017/S0017089508004230},
	url = {http://dx.doi.org/10.1017/S0017089508004230},
	author = {Fernandes, V{\'\i}tor H.}
}
