There are different citation styles available but they are used for different purposes.
APA which is an acronym for American Psychological Association was developed to ensure consistency and it was tailor made for writings related to the sciences.
APA citation style is mostly used for Social Sciences which is inclusive of Psychology, Education, Criminal Justice, Economics, etc.
So, Jace would probably have to use APA style to cite for his Criminal Justice course.
He tells Jem he has perpetrated a near libel. A libel is a legal term meaning a published false statement that is damaging to a person's reputation. Atticus, is of course joking with Jem, but he asks the children to make the snowman a little less like Mr. Avery