 The Citation Style Language (CSL) is an open XML-based language to describe the formatting of citations and bibliographies.In some areas of the Humanities, footnotes are used exclusively for references, and their use for conventional footnotes (explanations or examples) is avoided.In these areas, the term "footnote" is actually used as a synonym for "reference", and care must be taken by editors and typesetters to ensure that they understand how the term is being used by their authors.