sentences:  These index numbers are now used throughout the art world, in art texts, and on art websites to uniquely identify specific works of art by specific artists.An example is the ' (), which is a four volume set published in 1996 with 2,580 illustrations in 1,540 pages.In this set, volume I is a biography and volumes II-IV contain a chronological listing of Monet's work; that is to say, volume II contains Wildenstein Index No.