The bibliographicCitation field hasn’t appeared in many of the Darwin Core datasets I’ve audited, but when it did, it usually contained the wrong data items.
A bibliographicCitation entry is metadata about a record. To quote from the Darwin Core Quick Reference Guide, a bibliographicCitation entry should be
A bibliographic reference for the resource as a statement indicating how this record should be cited (attributed) when used… The intended usage of this term in Darwin Core is to provide the preferred way to cite the resource itself - “how to cite this record”.
So bibliographicCitation is not for
(1) sources used to help with identifications. These belong in identificationReferences.
(2) sources used in a literature or online search for occurrences. These belong in associatedReferences.
It’s easy to become confused about bibliographicCitation if you were thinking that metadata belongs in the eml.xml file that accompanies a dataset in a Darwin Core archive.
That’s true, and an eml.xml file has plenty of options for storing information about a dataset, including long explanations that don’t really fit in a data table. But some metadata items belong in data tables, like the date/time of the last update of an individual record, in the modified field. Entries in the license field might also differ from record to record, although license is also a required field in eml.xml.
Then there’s meta.xml in the Darwin Core archive, which explains the structure of a data table by referring to external standards. In the case of bibliographicCitation, meta.xml points to http://purl.org/dc/terms/bibliographicCitation. That URL sends you on to https://www.dublincore.org/specifications/dublin-core/dcmi-terms/#bibliographicCitation. There you can find a brief explanation from the originators of the term bibliographicCitation, namely the librarians of the Dublin Core Metadata Initiative. (Metadata about metadata!)
The OBIS Darwin Core manual has additional advice for bibliographicCitation users:
bibliographicCitation allows for providing different citations on record level, while a single citation for the entire dataset can and should be provided in the metadata (see EML). The citation at record level can have the format of a chapter in a book, where the book is the dataset citation. The record citation will have preference over the dataset citation. We do not, however, recommend to create different citations for every record, as this will explode the number of citations and will hamper the re-use of data.
(Note: I’ve seen Darwin Core datasets in which bibliographicCitation contained a unique UUID for every single record, and in which those thousands of UUIDs were duplicated in occurrenceID. A Google search for any of those UUIDs didn’t return a result.)
So unless you have an important reason to provide citations for individual records in your dataset, you don’t need to include a bibliographicCitation field. If you do, though, please do not fill this field with the references you used for identifications, or with references to literature or online sources for your occurrence records.
I sometimes wish that Darwin Core hadn’t borrowed so faithfully from Dublin Core. Imagine if bibliographicCitation had been renamed toCiteThisRecord…
Robert Mesibov (“datafixer”); email@example.com