What kind of Gauss quadrature is this? I found a formula for Gauss quadrature on the following link: < What kind of Gauss quadrature is that in _Section 5.7, eq. 56_? It uses the constant $\frac{1}{2} \pm \frac{\sqrt{3}}{6}$. I can't match these weights with any Gauss quadrature variants found on the web. Thanks in advance

It's the usual Legendre polynomial of order 2. But remember, that is usually on the interval $[−1,1]$, whereas the link you give is over $[0,1]$. So instead of $\pm \frac1{\sqrt 3}$ it is $\frac12(1\pm\frac1{\sqrt 3})$.