Mathias Casiulis, Eden Arbel, Charlotte van Waes, Yoav Lahini, Stefano Martiniani, Naomi Oppenheimer, Matan Yah Ben Zion. "A geometric condition for robot-swarm cohesion and cluster–flock transition." Proceedings of the National Academy of Sciences, 2025. doi:10.1073/pnas.2502211122