RIEL, H. van. Ernst Heldring’s dagboek en herinneringen. BMGN - Low Countries Historical Review, [S. l.], v. 86, n. 2, p. 218–226, 1971. DOI: 10.18352/bmgn-lchr.1662. Disponível em: https://bmgn-lchr.nl/article/view/URN%3ANBN%3ANL%3AUI%3A10-1-101820. Acesso em: 25 apr. 2024.