@TECHREPORT\{IMM2001-01235,
    author       = "M. L. Andersen and M. Fedi and P. C. Hansen and V. Paoletti and A. Rapolla",
    title        = "Computational properties of algorithms for multi-level inversion of {3-D} potential fields",
    year         = "2001",
    number       = "",
    series       = "IMM-Technical Report-2002-16",
    institution  = "Informatics and Mathematical Modelling, Technical University of Denmark",
    address      = "",
    type         = "",
    url          = "http://www2.compute.dtu.dk/pubdb/pubs/1235-full.html"
}