Addressed to the director of the jourrnal, it should include the title in Spanish work, the section in which publication is requested, the acceptance by the authors of content sent, the sale of the publishing rights to SEFAC, non-publication after all or part of the manuscript and not be in the process of acceptance in another publication. The statement by each of the authors of potential conflicts of interest that may affect them in relation to the work performed are included. The first signatory will be considered lead author and responsible for communication with the Editorial Board of the journal. Your e-mail address and postal and telephone must be included in the letter. A maximum of six authors recommended. However they are most always admitted that its participation in the performance of work is justified. A model letter is available on www.sefac.org. In order to complete the documentation for emailing the letter with signatures of authors it can be scanned and sent in .pdf format or by fax: 986 436 961.