1. Theory of Functionals and of Integro-Differential Equations;Volterra,1955
2. The Volterra and Wiener Theories of Non-linear Systems;Schetzen,1980
3. The use of functionals in the analysis of non-linear physical systems;Barrett;Journal of Electronics Control,1963
4. Equivalent linearization techniques;Caughey;Journal of the Acoustical Society of America,1963
5. Random vibration of systems with non-linear restoring forces;Crandall,1963