Which historical document contains references to the study of urine?

The Edwin Smith Surgical Papyrus is indeed the correct choice as it is one of the oldest known medical texts and provides insights into surgical practices and the study of various body fluids, including urine. This ancient Egyptian document, dating back to around 1600 BCE, includes case studies that are notably among the earliest references to medical examination techniques, which encompass observations on urine as part of diagnosis.

This document stands out because it reflects the early understanding of conditions based on clinical observations, including the analysis of bodily fluids to inform treatment strategies. The other options, while historically significant, do not focus on the analytical study of urine in a medical context. The Code of Hammurabi deals primarily with legal codes, the Hippocratic Corpus relates to general medical texts attributed to Hippocrates, and The Art of War focuses on military strategy. None of these directly address the examination or interpretation of urine as a diagnostic tool or its relevance in medical practice.