Presented below is a comprehensive index of literature of known peer-reviewed sources on Vanishing Twin Syndrome (VTS) published primarily over the past 20 years (with limited exceptions for landmark studies before that time). This index was developed by Nichole Cubbage and Carolina Negrin. Sources are organized into three primary categories (i.e., Clinical Evidence, Patient Experience & Communication, and Ethical/Policy Context), each with corresponding subcategories to support structured navigation and analysis. Please note: Some studies may overlap with multiple categories but may only be listed in the most relevant section to mitigate data redundancy..