This document provides guidelines for the preparation of bibliographic references. It also gives guidelines for the preparation of citations in works that are not themselves primarily bibliographical. It is applicable to bibliographic references and citations to all kinds of information resources, including but not limited to monographs, serials, contributions within monographs and serials, patents, cartographic materials and diverse electronic resources (including research datasets, databases, programs and applications, web archives and social media, music, recorded sound, prints, photographs, graphic and audio-visual materials, archival sources and moving images). This document does not specify a data model for machine-readable citations, although such specification may be added to a later edition of this document. Guidelines for legal citations, such as for references to cases, statutes or treatises, are not addressed in this document, since such guidelines are country-specific3. Making recommendations as regards what kind of information resources may or may not be cited, or describing the risks involved with e.g. citing social media, is not within the scope of this document4. Providing the reasons for importance of citations in science is not within the scope of this document. A few examples of sources which should always be cited are given in Clause 5. Annex A refers to the relevant clauses of this document which explain the requirements for referencing or citing printed and electronic documents. Annex B specifies practices for referencing archived Web information resources.