A journal's Total Citations is a count of all citations to articles in the journal during its lifetime. The graph and table above show Total Citations by calendar year, i.e. 2018 Total Citations for a journal is the total sum of all citations that the journal received in 2018 regardless of the year of publication of the articles that have been cited. Note that the Total Citations count is calculated using data from the Scopus database. For journals which are not indexed in Scopus, secondary citations (i.e. citations derived from the references of documents which are indexed in Scopus) are considered.