@manual{UML21Spec,
	title = {Unified Modeling Language: Superstructure, version 2.1.1},
	author = { OMG},
	editor = { OMG},
	key = {UML 2.1.1},
	month = {February},
	number = {{OMG} document formal/2007-02-03},
	organization = {Object Modeling Group},
	year = {2007},
	biburl = {http://www.bibsonomy.org/bibtex/2d424f4608e04e7e05b795daee88aabfb/fparreiras},
	keywords = {uml }
}