Enhancement of elliptic flow can signal a first-order phase transition in high-energy heavy-ion collisionsYasushi Nara, Harri Niemi, Akira Ohnishi, Jan Steinheimer, Xiaofeng Luo and Horst StöckerEur. Phys. J. A, 54 2 (2018) 18DOI: https://doi.org/10.1140/epja/i2018-12413-x