Riferimenti: [http://www.thesouthernscribe.com/pen-articles/the-famous-bock-nib-works.html], [http://www.fountainpennetwork.com/forum/index.php?/topic/20363-nib-history], [https://history.evonik.com/sites/geschichte/en/Pages/default.aspx] <noinclude> {{BrandData|Date=1873|Place=Frankfurth|ProdDate=1932|Country=DE|Fullname=Deutsche Gold und Silber Scheideanstalt}}
Riferimenti: [1], [2], [3]