- ArchiefA539 - Sarah Gertrude Millin Papers
- ReeksB - Letters from S. G. Millin
- BestanddeelB1 - To her family
- BestanddeelB21 - To friends - regular (original or carbon copies)
- BestanddeelB22 - To friends (occasional)
- BestanddeelB31 - To literary agents and publishers
- BestanddeelB33 - Impersonal, about politics and social matters
- 2 more...