Quadratic Dirac point and valley topological phases in acoustic analogues of AB-stacked bilayer grapheneYuxin Qi, Huifen Gao, Taorui Qin, Jialuo Liang, Weiyin Deng, Xueqin Huang, Jiuyang Lu and Zhengyou LiuEPL, 134 3 (2021) 37002DOI: https://doi.org/10.1209/0295-5075/134/37002