收集的 latex 箭頭:
LaTeX - 可伸縮箭頭:
https://my.oschina.net/shaodongtang/blog/2248961
tikz的箭頭釋疑:
http://softlab.sdut.edu.cn/blog/subaochen/2017/05/tikz%E7%9A%84%E7%AE%AD%E5%A4%B4%E9%87%8A%E7%96%91/
LaTeX技巧931: 讓你的公式帶上箭頭指示:
https://www.latexstudio.net/archives/11822.html
https://ctan.org/pkg/witharrows
LaTeX中TikZ繪圖備忘一:
https://blog.csdn.net/weixin_44420912/article/details/86418033