JVV: Van De Vegte, J.. Feedback Control Systems. RMS: Rohrs, C., J. L. Melsa and D. G. Schultz. Linear Control Systems(Check Status) GVV: Gelb, A., and W. E. Vander Velde. Multiple-Input Describing Functions and Nonlinear System Design. FPE: Franklin, G. F., J. D. Powell, and A. Emami-Naeini. Feedback Control of Dynamic Systems.