Following the advice there, I would say that the relationship between the article and the publication is an entity itself. If your REST API represents essentially database calls, then it would be two operations: one on article and one on the article-to-publication link entity.
Edit: I suppose with this answer I was also assuming something different than the title. That it is potentially a many-to-many relationship between article and publication. If it is a 1-to-many relationship from publication to article, then it seems fair that article could be a sub-entity of publication.
For further actions, you may consider blocking this person and/or reporting abuse
We're a place where coders share, stay up-to-date and grow their careers.
Forgive me -- the linked post is not a direct answer, but I think gets at the heart of the issue.
Things that happen in relationships are the things that matter.
Following the advice there, I would say that the relationship between the article and the publication is an entity itself. If your REST API represents essentially database calls, then it would be two operations: one on article and one on the article-to-publication link entity.
Edit: I suppose with this answer I was also assuming something different than the title. That it is potentially a many-to-many relationship between article and publication. If it is a 1-to-many relationship from publication to article, then it seems fair that article could be a sub-entity of publication.