1. M. Schetzen: The Volterra and Wiener Theories of Nonlinear Systems, John Wiley & Sons, 1980. 531 p.
2. N. Wiener. Nonlinear problems in random theory. The Technology Press, MIT and John Wiley & Sons Inc. New York, 1958.
3. A. Back & A.C. Tsoi: Identification of nonlinear processes using Laguerre functions. Proceedings of EANN'95, Otaniemi, 21–23 August 1995, Finland.
4. G. Schram, M.G.H. Verhaegen & A.J. Krijgsman: System Identification with orthogonal basis functions and neural networks. Preprints of the 13th IFAC World Congress, San Fransisco, USA, 30th June–5th July 1996, Volume I pages 221–226
5. A. Visala & A. Halme: Qaulity Assurance in Bioprocesses by Model Based Fault Diagnosis and State Estimation. Preprints of the 13th IFAC World Congress, San Fransisco, USA, 30th June–5th July 1996, Volume N pages 425–430.