"Frequenz", 31.5 (1977): 133-166. Retrieved 23 May. 2013, from http://www.degruyter.com/view/j/freq.1977.31.5/issue-files/freq.1977.31.5.xml

Frequenz (1977), 31(5), pp. 133-166. Retrieved 23 May. 2013, from http://www.degruyter.com/view/j/freq.1977.31.5/issue-files/freq.1977.31.5.xml

Frequenz. 1977. 31(5): 133-166. Retrieved 23 May. 2013, from http://www.degruyter.com/view/j/freq.1977.31.5/issue-files/freq.1977.31.5.xml