Lectures on Mathematical Statistics (Chen Jiading, Sun Shanze, Li Dongfeng, Liu Liping, Higher Education Press): The textbooks of Peking University are very rich, extensive and profound, and they are excellent works.

Course of Mathematical Statistics (Chen Xiru, Ni Guoxi, University of Science and Technology of China Press);

Complex function and its application (zhanghua's translation of Mathematics): A good book, with few sections, easy to read and understand, and clear description.

Concise Complex Analysis (Gong Sheng, Peking University Publishing House): When I was chatting with my teacher recently, the teacher recommended this book when asked about the complex function. I haven't bought it yet, but I believe it must be true. Gong Sheng is a great generation. Please search for details.