@CONFERENCE\{IMM2003-01650,
    author       = "L. K. Hansen and K. B. Petersen",
    title        = "Monaural {ICA} of white noise mixtures is hard",
    year         = "2003",
    pages        = "815-820",
    booktitle    = "Proceedings of {ICA'}2003 Fourth Int. Symp.. on Independent Component Analysis and Blind Signal Separation, Nara Japan, April 4,",
    volume       = "",
    series       = "",
    editor       = "",
    publisher    = "",
    organization = "",
    address      = "",
    url          = "http://www2.compute.dtu.dk/pubdb/pubs/1650-full.html",
    abstract     = "Separation of monaural linear mixtures of `white' source signals
is fundamentally ill-posed. In some situations it is not possible
to find the mixing coefficients for the full `blind' problem. If
the mixing coefficients are known, the structure of the source
prior distribution determines the source reconstruction error. If
the prior is strongly multi-modal source reconstruction is
possible with low error, while source signals from the typical
`long tailed' distributions used in many {ICA} settings can not be
reconstructed. We provide a qualitative discussion of the limits
of monaural blind separation of white noise signals and give a set
of `no go' cases."
}