@misc{nlambda-code,
	author    = {Michal Szynwelski},
	title     = {{N}\lambda},
	note      = {Website},
	url       = {http://www.mimuw.edu.pl/~szynwelski/nlambda/},
	urldate   = {2018-08-14}
}

@misc{OMGUML2,
	author    = {Object Management Group ({OMG})},
	title     = {Unified modeling language specification: Version 2, revised final adopted specification}
	note      = {Website},
	url       = {http://www.uml.org/#UML2.0},
	year      = {2004},
	urldate   = {2012-07-23}
}