KNÜPPEL, Michael. Briefe Johann Reinhold Aspelins an Richard Andree aus den Jahren 1890–1892. Folia Orientalia, [S. l.], v. 54, p. 181–189, 2026. Disponível em: https://wydawnictwo.pan.pl/index.php/fo/article/view/6768. Acesso em: 8 oct. 2026.