Aurora Universities Network
A publication with different versions (e.g. pre-print, article) contributes to only one year, the year of the most frequent well-formatted date. If not available, then the year of the most recent and complete date among those that are well-formatted. Therefore, one publication can contribute with the year when the pre-print was deposited, while another with the year of publication, based on the quality of metadata records OpenAIRE collects.