1. http://www.alvin-portal.org/
(2017)
2. http://urn.kb.se/resolve?urn=urn:nbn:se:alvin:portal:record-12537/
3. http://urn.kb.se/resolve?urn=urn:nbn:se:alvin:portal:record-100958
4. http://ucl.ac.uk/library/special-collections/a-z/ben-tham
5. https://sok.riksarkivet.se/digitala-forskarsalen