Din Tong-Ren, Li Cheng-Zhi. Ordinary differential equations (second edition). Beijing. 2002.

丁同仁，李承治。常微分方程(第二版).北京。2002。

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My story is too ordinary, or over-ordinary. I can't understand why it touches readers so much. And this is my only very source of courage to have its English edition published.

我所讲述的故事实在过于平常，甚至过于平淡，我至今依然不知道为何会让读者们如此之伤感和心动，这也正是我决心出版英文版的唯一的勇气来源。

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