# Johann Häffner
**Wikidata**: [Q55936049](https://www.wikidata.org/wiki/Q55936049)  
**Source**: https://4ort.xyz/entity/johann-h-ffner


## References

1. Catalog of the German National Library
2. BnF authorities
3. CERL Thesaurus
4. [Source](http://thesaurus.cerl.org/record/cni00082108)
5. [Source](http://thesaurus.cerl.org/record/cnp01953361)