@book { ManagementinberufsbildendenSchulen, title = "Management in berufsbildenden Schulen", subtitle = "Zur Funktion des Schulleiters", author = "Michael {Szewczyk}", year = "2005", publisher = "Peter Lang Verlag", address = "Berlin, Germany", url = "https://www.peterlang.com/document/1098352" }