If there is a dispute about who created something, or who owns copyright in it, which cannot be resolved by negotiation, it may need to be resolved by a court. A court considers all the relevant evidence. The most important is usually the oral evidence of the parties to the dispute and the evidence of any witnesses. Other evidence may include a copy of any agreement (between a graphic designer and his or her client, for example), and drafts or digital files. A copyright notice on the work may indicate who claims ownership, but it is not necessarily conclusive.