"Frequenz", 41.9 (1987): 217-248. Retrieved 25 May. 2013, from http://www.degruyter.com/view/j/freq.1987.41.9/issue-files/freq.1987.41.9.xml

Frequenz (1987), 41(9), pp. 217-248. Retrieved 25 May. 2013, from http://www.degruyter.com/view/j/freq.1987.41.9/issue-files/freq.1987.41.9.xml

Frequenz. 1987. 41(9): 217-248. Retrieved 25 May. 2013, from http://www.degruyter.com/view/j/freq.1987.41.9/issue-files/freq.1987.41.9.xml