L. Kaizer, W., A. G. Pereira, and M. Ritt. “Sequencing Operator Counts With State-Space Search”. Proceedings of the International Conference on Automated Planning and Scheduling, vol. 30, no. 1, June 2020, pp. 166-74, https://ojs.aaai.org/index.php/ICAPS/article/view/6658.