Self-citation. There are no recommendations on acceptable volumes, it appears. Of course, the author must first determine this independently, applying ethical principles (if there is an urgent need to refer to our own work, then we refer). The journals do not write about this on their sites (or they do?). They also do not write (or do?) about self-citations by the journal itself (in the latest articles of the journal, the articles published earlier are cited).

It is, however, interesting. Ukrainian journals (according to the publisher affiliation) in Scopus for 2017  have been analyzed. About 40 active journals (this small amount is due to the fact that translations of about 15 journals are published by foreign publishers) were found, not a lot. So, what do we have? Only two journals did not cite themselves at all (in 2017, they did not publish their articles – either they were not indexed anymore, or it was a mistake): Electronic Journal of Theoretical Physics (27 citations); Fiziolohichnyi Zhurnal (37 citations). The self-citation leaders are: Problemy radiat͡siĭnoï medyt͡syny ta radiobiolohiï (36 articles published, 16 citations, including 11 self-citations); Nuclear and Radiation Safety (34; 13; 7); Nuclear Physics and Atomic Energy (44; 29; 15); Uspehi Fiziki Metallov (11; 22; 11).

It is interesting how this correlates with the subject area, which the journal relates to (there will be some error, because some journals are multidisciplinary or refer to several branches). It is interesting nevertheless. Every area has journals using many self-citations or few. However, there is one branch where all our (domestic) journals self-cite very much (from 30 to 53 percent), we say about Energy! Mathematics; Biochemistry, Genetics and Molecular Biology are branches whose journals cite themselves less than others.

It should be noted here that journals differ in the number of articles published, which may factor into the result. There are other factors.