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. 
However, guidelines for references to legal materials can also be found on
pages 216-224 in the 6 th of the Publication Manual of the APA .
The following sample reference to a statute in a state code and its
explanation can be found on page 220:
Mental Care and Treatment Act, 4 Kan. Stat. Ann.§§ 59-2901-2941 (1983 &
Explanation: This Kansas act can be found in codified version between sections 2901 and 2941 in Chapter 59 of volume 4 of the 1983 edition of Kansas Statutes Annotated. Two amendments to the act and additional references are provided in the 1992 supplement for the Kansas Statutes Annotated.