feat: update readme

README.md

@@ -10,3 +10,10 @@
 | LeibnizFormula          | $\pi$ 的莱布尼茨公式      | [leibniz-formula](https://hatter.ink/static/resource/muboard/?id=leibniz-formula&version=1)                                 |
 | EulerNumber             | 欧拉数                | [eulers-number](https://hatter.ink/static/resource/muboard/?id=eulers-number&version=latest&full=1)                         |
 | BirthdayParadox         | 生日悖论               | [birthday-paradox](https://hatter.ink/static/resource/muboard/?id=birthday-paradox&version=latest&full=1)                   |
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+
+<br>
+
+Mathematics:
+- https://github.com/OI-wiki/OI-wiki
+- https://github.com/valeman/Awesome_Math_Books