Clever algorithm. The java code is [available on the net](https://github.com/drovandi/GraphCompressionByBFS). In 2009, it was almost simultaneously published with [Permuting Web and Social Graphs](https://papers-gamma.link/paper/177) of Boldi et al. At this time it is better than Boldi et al. solution in many cases. The Apostolico-Drovandi paper is mentioned as "The only coordinate-free compression algorithm we are aware of" in [another](https://papers-gamma.link/paper/105) Boldi et al. paper which was published after a while. At that time Boldi et al. provide better results.
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?