[R] Crossed Random Effects ?

[Wilhelm B. Kloke]

I have been asked how to handle the following situation in R:

Given an unbalanced design of 3 crossed random effects, such as
subject, rater and item, how to estimate the variance components?

I know how to do it using lme, but this seems to be limited to
the nested case; or to use aov with error strata, when the
design is balanced. 
-- 
Dipl.-Math. Wilhelm Bernhard Kloke
Institut fuer Arbeitsphysiologie an der Universitaet Dortmund
Ardeystrasse 67, D-44139 Dortmund, Tel. 0231-1084-257