I. General description A head consists of 5 parts: (1) Publisher information (2) Journal information (3) Issue information (4) Document type (5) Article information II. Meaning of codes Tags + = tag will be present 1 or more times ? = tag will be present 0 or 1 time 1-n = tag will be present 1 to n times Text ... = text is always present III. Description of head 0 + = beginning of head 1 = publisher information ... = publisher name ... = publisher location = end publisher information 2 = journal information ... = ISSN ... = journal title ... = journal URL = end journal information 3 = issue information ... = volume number ... = issue number ... = cover date ... = issue URL = end issue information 4 ... = document type 5 = article information ... = title = author group + = author ? ... = author's given name(s) ... = author's surname ? ... = author's name suffix, e.g., Jr. or III + = end author = end author group = page numbers ... = first page ... = last page = end page numbers ? ... = abstract ... = link to article citation, abstract and full-text options ... = DOI (Document Object Identifier) ? ... = link to article dataset ? ... = link to article additional materials = end article information + = end head