is considered a joint contribution, not creditable to only one of them or to one more than the other. For the purpose of credits (and to discourage later disputes), one of the writers must openly question the designation of their contributions being part of a team at the time the work is submitted to the Writers Guild if they wish to be credited in another way. A team is credited with an ampersand (&) separating their names. Team credits are more complex when one of the team has also been hired as an additional writer: both writers in the team must form an agreement to allow the additional writer to take the shared credit. Multiple writers who are not part of a team have the word "and" separating their names. Written by The "Written by" credit is for writers who can claim both the story and teleplay/screenplay elements, except when there is "source material of a story nature". There are some restrictions on producers and directors of a work being given writing credits, particularly that they cannot receive the story/screenplay/teleplay credit unless there are either no other writers for the story/screenplay/teleplay or the decision is taken to arbitration, and that the Writers Guild must have been notified of a writing team (intending to claim credits) that includes a producer/director and a non-producer/director at the commencement of the team's work together. In television, a written by credit is also usually given to writers on variety shows and audience participation shows. Screenplay by A "Screenplay by" credit may also be used, when the writers for the story and screenplay are different, or in similar circumstances to a screen story credit (either if the work is not mostly original, or in addition to the screen story credit). No more than two writers can share a screenplay credit except in cases of arbitration. From arbitration, screenplay credits can be given to either three individual writers or two teams of writers. For the purposes of arbitration, to be awarded a screenplay credit, the writer must have contributed more than 33 percent of the final screenplay. In the case of an original screenplay, Writers who did not write the original must contribute more than 50 percent to receive the credit. The WGA acknowledges the difficulty in determining such percentages. The television equivalent of the screenplay by credit is "Teleplay by", and it is used in the