@BOOK\{IMM1998-0446,
    author       = "P. C. Hansen",
    title        = "Rank-Deficient and Discrete Ill-Posed Problems. Numerical Aspects of Linear Inversion",
    year         = "1998",
    volume       = "",
    number       = "",
    series       = "",
    publisher    = "SIAM",
    address      = "Philadelphia",
    edition      = "",
    url          = "http://www2.compute.dtu.dk/pubdb/pubs/446-full.html"
}