Bloomsbury 

Locating Paintings - When you know the location of a painting in a public collection, much of the research work is done for you already.

Wright, Christopher.   The world’s master paintings: from the early Renaissance to the present day : a comprehensive listing of works by 1,300 painters and a complete guide to their locations worldwide.   London ; New York : Routledge, 1992.    Lilly Library 750.74 W948, W927, 1992

Catalogues Raisonnés
"All the works of an artist".  A scholar or a group of scholars documents every work of an artist's career.  Each work is pictured, with scholarly opinions, provenance (where the work has been), literature about the work, and spurious works (forgeries).  The first place to start when researching an artist or individual work. Not all artists have catalogues raisonnés.

Watney, Simon.   The art of Duncan Grant.  London : John Murray, 1999.  Lilly Library  ND497.G68 W38 1999  

Permanent Holdings Catalogs (of museums)

Detailed catalogs of a period or genre of art in a particular museum.  Like a catalogue raisonné, it will contain a collection of scholar's opinion on an object, conservation reports, provenance and literature (written about it).  If you know of the location of a work of art, check for permanent holdings catalogs.