Xavier, here is a link to artbusiness.com and there is a wealth of information in the form of free articles,many of which I have read and find very informative.
http://www.artbusiness.com/artists.html
Here is a short bio on the sites founder. Site principal, Alan Bamberger, is an art consultant, advisor, author, and independent appraiser specializing in research, appraisal, and all business and market aspects of original works of art, artist manuscript materials, art-related documents, and art reference books. He has been selling art since 1979 and rare and scholarly art reference books since 1982, and has been consulting and appraising for artists, galleries, businesses, organizations and collectors since 1985.