Löbbe, Klaus; Siebe, Thomas - In: Mitteilungen aus der Arbeitsmarkt- und Berufsforschung 28 (1995) 4, pp. 562-572
"There is no universal definition of the term 'sector of industry'; sectors should be demarkated according to the objectives of respective studies, if they are going to make any sense. Based on a few criteria for consistency as well as substantially adequate statistical data and economic...
