OR InsightJuly 1989, Volume 2, Issue 3, pp 24–24 | Cite asLetters to the EditorAuthorsAuthors and affiliationsBrian DangerfieldLetter to the EditorFirst Online: 01 July 1989 22 Downloads Download to read the full article textCopyright information© Operational Research Society 1989Authors and AffiliationsBrian Dangerfield11.University of Salford