1. Lectures on the Identification Problem - The Least Squares Method;Åström,1968
2. Solving linear least squares problems by Gram–Schmidt orthogonalization;Björck;BIT,1967
3. Clarke, D. W. (1967). Generalized–least-squares estimation of the parameters of a dynamic model. IFAC Symp. on Identification in Automatic Control Systems, Prague, paper 3.17.
4. Clarke, D.W., and P.J. Gawthrop, (1979). Implementation and application of microprocessor-based self-tuners. IFAC Symp. on Identification and Syst. Param. Estimat., Darmstadt, Vol. 1, 197–204.
5. De Keyser, R., (1979). On the relationship between some well-known recursive identification methods -the recursive tally principle. IFAC Symp. on Identification and Syst. Param. Estimat., Darmstadt, Vol. 1, 251–257.