Abstract（頁13，28）；1. Introduction（頁14-15）；2. Detection of periodic orbits and subharmonic orbits（頁15-16）；3. Stability of periodic orbits and subharmonic orbits（頁16-17）；4. Codimension-two bifurcation in a coupled Duffing euqtion with twisted frequency-response curves（頁17-20）；5. Conclusions（頁20-21）；References（頁21-22）
