51³Ô¹Ï

I am a little confused. Was Jonathan Levitt and Mike Thelwall's research on the frequency of citation of multidisciplinary research itself multidisciplinary? If so, does the publication of their citation in 51³Ô¹Ï (Letters, 16 October) contribute towards proving or disproving their thesis?

A. H. Harker, Department of physics and astronomy, University College London.