1. Booton, R. C., 1953, “The Analysis of Nonlinear Central Systems With Random Inputs,” Proc. Symp. on Nonlinear Circuit Analysis, Polytechnic Institute of Brooklyn, and also (1954), IRE Transactions on Circuit Theory1, pp. 32–34.
2. Kazakov, I. E. , 1954, “An Approximate Method for the Statistical Investigation of Nonlinear Systems” (in Russian), Trudi Voenna-Vozdushnoi Inzhenernoi Akademii imeni Professora N. E. Zhukowskogo, 394, pp. 1–52.
3. Kazakov, I. E. , 1956, “Approximate Probabilistic Analysis of the Accuracy of the Operation of Essentially Nonlinear Systems,” Avtom. Telemekh., 17, pp. 423–450.
4. Caughey, T. K. , 1959, “Response of Nonlinear String to Random Loading,” ASME J. Appl. Mech., 26, pp. 341–344.
5. Caughey, T. K. , 1963, “Equivalent Linearization Techniques,” J. Acoust. Soc. Am., 35, pp. 1706–1711. Reference is made to presentations in Cal Tech Lectures in 1953.