Answer:
Historians include citations in an essay for ideas they quoted directly or that support their argument.
Step-by-step explanation:
Citation is a reference to a book, article, material, web page, or other published item. It helps to inform readers that certain idea is from another source. It must be coincise to give a detailed means of identifying the item uniquely. Different citation styles are used in scientific citation, legal citation, prior art, the arts, and the humanities. It is very important as it reveals the quality of work that supports a writing.
So majorly, historians include citations in an essay for ideas they quoted directly or that support their argument.