Mathematical Physics: Classical Mechanics
《Mathematical Physics: Classical Mechanics》 · 第 11 页 · Chapter 1，Definition 1.4 及正交叉的约定
A positive crossing shows one strand (either one) passing the other in the manner of a “right-hand screw”. […] Suppose that \(L\) is a two-component oriented link with components \(L_1\) and \(L_2\). The linking number \(\operatorname{lk}(L_1,L_2)\) of \(L_1\) and \(L_2\) is half the sum of the signs, in a diagram for \(L\), of the crossings at which one strand is from \(L_1\) and the other is from \(L_2\).