ISSNs are not included in an APA 7th reference list or in a Chicago 17th bibliography.
APA 7th
Where no DOI is given for an electronic resource, do not include a URL including database information in the reference. Where an electronic article has been found on the internet (i.e. not through a library search), give the full URL to the web page where it was found.
Chicago 17th Notes & Bibliography
In the absence of a DOI, look for a persistent link, often available with the electronic resource. Sometimes a suitable URL will not be available and in such cases, include the name of the database rather than the URL.
