Stiens, G. (1983). On the Future of Spatial and Settlement Structures: Long-Term Projections of Developments in the Federal Republic of Germany.
توثيق أسلوب شيكاغو (الطبعة السابعة عشر)Stiens, Gerhard. On the Future of Spatial and Settlement Structures: Long-Term Projections of Developments in the Federal Republic of Germany. Bonn, 1983.
توثيق جمعية اللغة المعاصرة MLA (الطبعة الثامنة)Stiens, Gerhard. On the Future of Spatial and Settlement Structures: Long-Term Projections of Developments in the Federal Republic of Germany. 1983.
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