SCHRÖDER, H. J. Julius Carl Ertel: Ein Hamburger Industrieller. [s.l.] : Hamburg University Press,2017. v. 19 DOI: 10.15460/HUP.MFW.19.175. Disponível em: https://hup.sub.uni-hamburg.de/oa-pub/catalog/book/173. Acesso em: 21 nov. 2024.