- 1973 to 19744
- 1975 to 197913
- 1980 to 19843
- 1985 to 19895
- 1990 to 19944
- 1995 to 19991
- 2000 to 200452
- 2005 to 200915
- 201031
The preservation of the Duke University Libraries Digital Collections and the Duke Digital Repository programs are supported in part by the Lowell and Eileen Aptman Digital Preservation Fund