Chetwynd-Tutton, S.J. (1974) Generalised grid technique and some
associated methodological problems. Unpublished doctoral dissertation,
University of London, London, UK.
Janet Chetwynd-Tutton was a PhD student of Patrick Slaters' (Dr Slater was
one of the few people at the time to have access to main frame means of
analysing grids) (I'm taking a big risk here but Beverly Walker knows -
she suggested I read it about 4 or 5 years ago) and I believe she
conducted multiple analyses of large repertory grids (+20 x +20, as was
the fashion then) reducing the number of randomly selected constructs and
elements and measuring the impact on the first 3 principle components.