Coexistence, bifurcation and chaos of a periodically forced duffing system with absolute nonlinearityJiayun Chen, Fuhong Min, Qiusen Jin and Biaomin YeEur. Phys. J. Special Topics, 228 6 (2019) 1405-1419DOI: https://doi.org/10.1140/epjst/e2019-800221-1