Cressie & Read (1989) Weighted Median Polish

Hi 
I am trying to implement the weighted median polish
method described in Cressie, Statistics for Spatial
Data Revised Ed' page 398.  The median polish bit
looks simple but I can't understand the weighting
described in section 3.3.13, p147.  Sadly I don't have
access to either of the referenced papers.

Could anyone explain the weighting to me so I can
impliment the method in R, or does anyone have some R
code for this?

Many thanks
Dave

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