SPE policy requires that SPE hold copyright to all copyrightable material in its publications, including conference proceedings, and to the individual contributions contained therein, to protect the interests of SPE, authors and their employers, and at the same time, to facilitate the appropriate re-use of this material by others. SPE distributes its publications throughout the world and does so by various print and electronic means. SPE also may translate or authorize translation of its publications, and articles contained therein, for inclusion in various publications. Transfer of copyright to SPE is a requirement for publication, including publication in conference proceedings, with the exception of material that is in the public domain (i.e., is not subject to copyright). Publications are critical in SPE's mission to collect and disseminate knowledge concerning the exploration, development and production of oil and gas resources, and related technologies, for the public benefit; and to help industry professionals enhance their technical and professional competence.