Fig 1. Illustrative example of COI relationship between different authors.
Where Pn and Am are the list of articles and authors respectively, red dashed line indicates citing relationship. The figure shows two cases: (1) Before Pi cites Pj, the author(s) of Pi has (have) collaborated with the author(s) of Pj, just like P2 cites P1, Author A1 and Author A3 co-author P5, Author A1 and Author A4 co-author P6, that is to say, there are two co-author pairs (A1, A3), (A1, A4); (2) Before Pi cites Pj, the author(s) of Pi has (have) not collaborated with the author(s) of Pj, just like P3 cites P2, however, if author A3 and author A5 belong to the same affiliation, (A3, A5) composes suspect COI author pair.