The ISSN registry (and usually the relevant national copyright library, I think) Both examples mentioned turn up on an ISSN search Antarctica Journal of Mathe

The ISSN registry (and usually the relevant national copyright library, I think) Both examples mentioned turn up on an ISSN search Antarctica Journal of Mathematics https://portal.issn.org/resource/ISSN/0972-8643 https://portal.issn.org/resource/ISSN/0972-8643 published in India from 2004 according to the Indian registry http://nsl.niscair.res.in/ISSNPROCESS/issnassignedinfo.jsp http://nsl.niscair.res.in/ISSNPROCESS/issnassignedinfo.jsp Journal of combinatorics and number theory https://portal.issn.org/resource/ISSN/1942-5600 https://portal.issn.org/resource/ISSN/1942-5600 published in the US Details of holdings at https://search.worldcat.org/title/228503731 https://search.worldcat.org/title/228503731