Citation patterns are also known to be affected by unethical behavior of both the authors and journal staff. Such behavior is called impact factor boosting, and was reported to involve even the top-tier journals. Specifically the high-ranking journals of medical science, including the Lancet, JAMA and New England Journal of Medicine, are thought to be associated with such behavior, with up to 30% of citations to these journals being generated by commissioned opinion articles.  On the other hand, the phenomenon of citation cartels is rising. Citation cartels are defined as groups of authors that cite each other disproportionately more than they do other groups of authors who work on the same subject. 
The purpose of APA in text and parenthetical citations is to give the reader a brief idea as to where you found your information, while they’re in the middle of reading or viewing your project. You may include direct quotes in the body of your project, which are word-for-word quotes from another source. Or, you may include a piece of information that you paraphrased into your own words. These are called parenthetical citations. Both direct quotes and paraphrased information include an in text citation directly following it. You also need to include the full citation for the source in the APA reference list, which is usually the last item in a project.