Catalytic condensation of phenol with formaldehyde into BPF on recyclable anchoring sulfuric acidHui Li, Xi Cao, Huiting He, Jian Liu, Weijian Xiang, Jialuo She and Dulin YinE3S Web Conf., 213 (2020) 01003DOI: https://doi.org/10.1051/e3sconf/202021301003