- CollectieMS/MS 01.138 - Congregationalism in Iowa 1840-1932
- 1 - Central Congregational Association of Iowa (2 Volumes)
- 2 - Central Congregational Association of Iowa, Treasurer's book
- 3 - Denmark Association of the Congregational Church
- 4 - General Congregational Association of Iowa (2 Volumes)
- 5 - Davenport Congregational Association of Iowa (3 Volumes)
- 6 - Des Moines River Association of the Congregational Church
- 7 - Julius Reed- Iowa Congregationalism; contributions to its history to 1869