I recently added parameters for catalogue raisonné references and accession numbers to the English Wikipedia's infobox for artworks:
http://en.wikipedia.org/wiki/Template:Infobox_artwork
you can see them in use on:
http://en.wikipedia.org/wiki/Sorrow_(Van_Gogh)
Please add them to the equivalent infobox for other langues; and make use of them in other articles, as appropriate.
-- Andy Mabbett @pigsonthewing http://pigsonthewing.org.uk