2Liu Jiang-feng, Ju Li, Blair David G. Vibration isolation performance of an ultra-low frequency folded pendulum resonator[J]. PhysicsLetters A. 1997, 228(4): 243-249.
3Liu Jiang-feng, Winterflood John, Blair David G. Transfer funstion of an ultralow frequency vibration isolation system[J]. Rev. Sci. Instrum.1995, 66(5): 3216-3218.