"Tagungen" Frequenz, 35.11 (1981): 290-290. Retrieved 24 May. 2013, from doi:10.1515/FREQ.1981.35.11.290

Tagungen. Frequenz (1981), 35(11), pp. 285-316. Retrieved 24 May. 2013, from doi:10.1515/FREQ.1981.35.11.290

Tagungen. Frequenz. 1981. 35(11): 285-316. Retrieved 24 May. 2013, from doi:10.1515/FREQ.1981.35.11.290