李 立. 董文渙《聲調四譜圖説》辯疑: A Criticism of Tung Wen-huan’s Four Charts of Tones Sequence. 人文中國學報, [S. l.], v. 8, p. 175–194, 2001. DOI: 10.24112/sinohumanitas.82371. Disponível em: https://ejournals.lib.hkbu.edu.hk/index.php/sinohumanitas/article/view/2371. Acesso em: 29 jul. 2024.