Which type of source presents an interpretation of existing work, often including citations?

A secondary source is a type of resource that interprets, analyzes, or summarizes information derived from primary sources. These sources are often characterized by their inclusion of citations and references to original works, showcasing the interpretations and insights of the author based on the data or findings of others. For example, a textbook reviewing findings from various research papers or a scholarly article that critiques and elaborates on earlier studies would be classified as secondary sources. This layer of analysis helps deepen understanding of a subject by providing context and additional perspectives that are not present in primary sources, which are original, firsthand accounts or data. The roles of primary, tertiary, and quaternary sources differ, with primary sources being original materials, tertiary sources summarizing and compiling information from primary and secondary sources, and quaternary sources typically providing further distillation or overview beyond tertiary sources. This makes the role of secondary sources particularly significant for research and analysis in various fields, including computer science.