The recurrence of citations within a scientific article

Although listed at the tail of a scientific article only once, a reference is usually cited repeatedly inside the full text of the article. In this research, we investigated the universality of recurring citations in Journal of Informetrics. About 1/4 references are repeatedly cited. For these repeatedly cited references, their citation location and citation context for the first and subsequent times are examined separately. Normally, recurring citations of a same reference tend to be located in the same section instead of different ones. It proves that, even if a reference is cited for multiple times in a single citing paper, it is still focus on the same topic in the same section most of the time. We also explored the reason why recurring citations are happening. By comparing the contexts of two kinds of citations, the first-time citations and the succeeding citations, we found that, for a specific reference, its first-time citation is usually not as intentional as the succeeding citations. Just because of the relative importance of the succeeding citations compared to the first-time citation, recurring citations are reasonable and necessary.