# Robert Haardt
**Wikidata**: [Q109997113](https://www.wikidata.org/wiki/Q109997113)  
**Source**: https://4ort.xyz/entity/robert-haardt


## References

1. Integrated Authority File
2. Virtual International Authority File
3. The Stuttgart Database of Scientific Illustrators 1450–1950
4. NUKAT
5. Catalogo of the National Library of India