This document discusses related literature and studies, their importance and functions in research. It defines related literature as published materials found in books, journals, and other sources that are relevant to the present study. Related studies are unpublished works like theses and dissertations. Related materials help researchers by guiding them in topic selection, understanding their topic better, avoiding duplication, and informing the research design. They are important for comparing findings to previous work and developing generalizations. The document provides characteristics, sources, and locations for finding related literature and studies.