Authors may request to withdraw a manuscript under certain circumstances. A withdrawal request should be sent in writing to the Editor-in-Chief as soon as possible, including a valid reason (e.g. discovery of errors, personal reasons). Requests made before peer review can be accommodated without penalty. However, after peer review or acceptance, withdrawal is generally discouraged except for serious reasons. Withdrawal after acceptance is effectively a retraction and is handled through the correction process. Authors should note that undue withdrawal wastes reviewer effort; therefore, papers under review should not be withdrawn without compelling cause. If the request is granted, the manuscript is removed from consideration, and a withdrawal notice may be recorded in our archive. Authors should not submit the same manuscript elsewhere simultaneously, as duplicate submission is prohibited.