@CONFERENCE\{IMM1980-0358, author = "H. Juel", title = "Fixed point optimality criteria for the Weber problem with arbitrary norms", year = "1980", booktitle = "The Institute of Management Sciences - Operations Research Society of America", volume = "", series = "", editor = "", publisher = "", organization = "", address = "", url = "http://www2.compute.dtu.dk/pubdb/pubs/358-full.html" }