Sources
- https://pipedia.org/index.php?search=Seiffert --Magna (talk) 04:50, 24 December 2020 (CST)
- https://www.companyhouse.de/Heinrich-Seiffert-Sohn-GmbH-Pfeifen-und-Tabak-Import-Kassel --Magna (talk) 04:49, 24 December 2020 (CST)
- https://www.youtube.com/watch?v=1DpHXPPdk74 --Magna (talk) 04:51, 24 December 2020 (CST)
- https://petersonpipenotes.org/tag/peterson-sillems/ --Magna (talk) 04:53, 24 December 2020 (CST)
- https://rallis.blog/2020/12/16/svendborg-pfeifen-esprit-und-fleiss/ --Magna (talk) 05:03, 24 December 2020 (CST)