Britannica, The Editors of Encyclopaedia (21 Jan 2021). "Emil Ludwig". Encyclopedia Britannica (dalam bahasa Inggris). Diakses tanggal 2021-09-10.
marxists.org
An Interview with the German Author Emil Ludwig Date of Interview: December 13, 1931
Date Published: 1932
Publisher: Co-Operative Publishing Society of Foreign Workers in the U.S.S.R., Moscow
Transcription/Markup: Brian Reid
Public Domain: Marxists Internet Archive (2007).
