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平台:
Brillonline Open Access Journals
(Available from 1919 volume: 1 issue: 1.)
DOAJ Directory of Open Access Journals
(Available from 2013 until 2012.)
JSTOR Arts and Sciences IX
(Available from 1992/01/01 volume: 66 issue: 1/2.)
JSTOR Arts and Sciences IX
(Available from 1960 volume: 40 until 1991 volume: 65.)
ProQuest Political Science Database
(Available from 2006/01/01.)