Authors must communicate any commercial link, material or financial help received during the research at the time of writing the article or its publication, or any potential financial interest in relation to the subject of their article and that could give rise to a conflict of interest. If there is no source of funding, the writing must include the section and state "The authors did not receive any sponsorship to carry out the research reported in the present manuscript". The authors who do not have any conflict of interest related to the subject of the work must also declare that "There is not any type of direct or indirect conflict of interest related to the subject of the work." This information must be placed at the end of each collaboration, in a visible place.