Wåhlin, E. (1978). Research on classification systems: Summarizing report on research on classification systems and their application. Swedish Council for Building Research.
Trích dẫn kiểu Chicago (xuất bản lần thứ 7)Wåhlin, Ejnar. Research on Classification Systems: Summarizing Report on Research on Classification Systems and Their Application. Stockholm: Swedish Council for Building Research, 1978.
Trích dẫn kiểu MLA (xuất bản lần thứ 8)Wåhlin, Ejnar. Research on Classification Systems: Summarizing Report on Research on Classification Systems and Their Application. Swedish Council for Building Research, 1978.
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