Opus numbers are, in Pleyel's case, very complicated. Publishers at Wien, Paris, London, Offenbach and Amsterdam/Berlin (i.e. Hummel) each used their own system of numbering, which leads to much confusion. Therefore it is also difficult to choose just one of the many opus numbers. Maybe it would be possible to include this kind of information in different colums. I would put the Benton number first, then in separate columns the different Opus numbers of the major publishing centers. Do you think we could include this in the Sortable list here, or would it be better to create a separate list for that purpose? See also the talk on Pleyel in the User Talk of KGill. Cgo 15:16, 20 November 2010 (UTC)