1. L. O. Chua and A. Ushida, ”Algorithm for computing almost periodic steady-state response of nonlinear systems to multiple input frequencies”, IEEE Trans. Circuits Syst., vol.CAS-28, pp. 953–971, 1981.
2. A. Ushida and L. O. Chua, ”A substitution algorithm for solving nonlinear circuits with multi-frequency components”, IEEE Trans. Circuits Syst., vol.CAS-31, pp.766–779, 1984.
3. D. Hente and R. H. Jansen, ”Frequency-domain continuation method for the analysis and stability investigation of nonlinear microwave circuits”, Proc. IEE, part H, vol. 133, pp. 351–362, 1986.
4. R. Gilmore, ”Nonlinear circuit design using the modified harmonic balance algorithm”, IEEE Trans. Microwave Theory Tech., vol.34, pp. 1294–1307, 1986.
5. V. Rizzoli, C. Cecchetti, A. Lipparini and F. Mastri, ”General-purpose harmonic balance analysis of nonlinear microwave circuits under multitone excitation”, IEEE Trans. Microwave Theory Tech., vol.36, pp. 1650–1660, 1988.