In a follow-up to a pilot study published in 2019, the authors collected student research papers from English Composition II courses at three public comprehensive universities from different regions in the United States to classify and compare the sources selected by students at each institution. Working with a representative sample of 712 bibliographic references, the authors used a research-tested taxonomy called The WHY Method to classify each source by three key attributes--"W"ho wrote each source, "H"ow it was edited, and wh"Y" it was published. The results of this cross-institutional study indicate that student source selection is affected most powerfully by the variables of which institution a student attends, student age, and whether the student is a first-generation university student. Student GPA, gender, class ranking (freshman, sophomore, and so on), and ethnicity were not statistically predictive factors. This study establishes the importance of institutional context in how students construct authority and provides librarians with a tool that enables them to better understand and describe that context. [For the 2019 pilot study, "Student Constructions of Authority in the Framework Era: A Bibliometric Pilot Study Using a Faceted Taxonomy," see EJ1211687.]