@article {Krogstie.2006.1,
	title = {A Longitudinal Study of General and Functional Maintenance in Norway},
	journal = {Information and Software Technology},
	volume = {48},
	number = {11},
	year = {2006},
	month = {November},
	pages = {993-1005},
	author = {Krogstie, John and Jahr, Arthur and Sj{\o}berg, Dag Ingar Kondrup}
}
