An improvement to Boldi-Vigna WebGraph. It uses Huffman coding, asymmetric numeral systems (a form of arithmetic coding) and a new hybrid integer encoding schema. The paper also mentions other algorithms like [Log(Graph) by Besta et al.](https://www.youtube.com/watch?v=j98N9nthr0M) and Apostolico-Drovandi method together with $k^2$-trees, 2D block trees, ZipG graph store... Author suggest the [Besta-Hoefler survey (2018) with more than 460 references](https://arxiv.org/abs/1806.01799) to any reader interested in lossless graph compression methods. The paper does not consider node permutations. The code is in [google's github account](https://github.com/google/zuckerli).
Furthermore, Apostolico and Drovandi suggest to use $\pi$-code, see Section 4 from [their paper](https://papers-gamma.link/paper/178), when the power law distribution have an exponent close to 1. It actually pushes me to ask, maybe a naive question: is there any standard method to construct such a code when the distribution of the gaps is given or estimated from the data?