“…Exceptions: Appleton (1984: 23-54);levitzky (1998: 77-92); Köllner (1999: 164-173). Only recently a more systematic attempt was made to find an appropriate approach to the solution of this problem, see Betz and Köllner (2000: 94-104), and Erdmann et al (2004); for case studies, see Erdmann (2002a), Köllner (2003: 352-376), and Betz (2003).…”