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MR2179976 (2006e:90058) Arriola, Rosario; Laporte, Gilbert; Ortega, Francisco A. The Weber problem in a multi-storey building. INFOR Inf. Syst. Oper. Res. 43 (2005), no. 3, 157--169. (Reviewer: Sandra L. Arlinghaus) 90B80 (90C90)