Publishing contracts are used to negotiate the terms by which a publishing house will publish an author's literary work. A literary work may also be self published, though this comes with its own set of obstacles and legal issues. While the rise of the world wide web has led to a rise in online self publishing, the majority of authors still continue to choose to have their works published by publishing houses, who are often better able to distribute and market an author's literary work. Authors should take care to make sure their publishing contract is fair, and consulting an attorney or other professional with specific expertise in publishing contracts is recommended. Attorneys often help negotiate the points of a publishing contract in order to gain an agreement that will be in the author's best interests. Issues relating to copyrights, advances and royalty payments, editing and publishing, and subsidiary rights such as the rights to move adaptations or audio book versions of a literary work are frequently negotiated.