This longitudinal study at a large public university surveyed students of the 2008 freshmen cohort over four years about their use of websites and library resources for their research papers. The three goals of the study were to track changes in reported research behavior over time, to see if students' reported source choices were associated with librarian instruction and/or if they were associated with instructors' source requirements. The study found that, as students matured, they used library resources more frequently. Librarian instruction and faculty source requirements both were associated with increased use of library resources.