A preprint is a version of a scholarly paper preceding formal peer review and publication in a peer-reviewed scholarly journal. CE allows authors to submit preprints to the journal, without considering this to be a duplicate submission or publication. CE recommends that authors disclose the existence of a preprint with its DOI in a letter to the editor during the submission process. Otherwise, a plagiarism check program—Similarity Check (Crosscheck) or Copy Killer—may flag the manuscript as containing excessive duplications. A preprint submission will be processed using the same peer-review process as a regular submission. If a preprint is accepted for publication, the authors should update the information on the preprint site with a link to the article published in CE, including the DOI for the CE article. It is strongly recommended that authors cite the article in CE instead of the preprint in their next submission to journals.