1. Minorsky, N., Nonlinear Oscillations (D. Van Nostrand Co. Inc., Princeton, N. J.1962), Chap. 14, pp.329-335.
2. Minorsky, N., Nonlinear Oscillations (D. Van Nostrand Co. Inc., Princeton, N. J.1962), Chap. 16, pp.390-415.
3. March 1961;Melbourne W. G.
4. Fig. 2;For