La science et l'hypothèse
《La science et l'hypothèse》 · 第 120–121 页 · Section 4.5，link diagram 的定义
A link diagram of a link \(L\) in \(\mathbb R^3=S^3-\{\infty\}\) is a generic projection of \(L\) into \(\mathbb R^2\) (to an immersion of \(\coprod_{i=1}^m S^1\) which is 1–1 except at transverse double points), together with information specifying which strand crosses underneath at each double point (denoted as in Figure 4.25).