1. Society, Politics and Economic Development. A Quantitative approach;Adelman,1967
2. Fractional fix-point (FFP) estimation;Ågren,1970
3. Ågren, A. (1972). Extensions of the fix-point method. Theory and applications. Doctoral Thesis, Univ. of Uppsala, Uppsala, Sweden.
4. Bergström, R. (1969). NIPALS and related methods for ID systems applied to Monte Carlo and real world data. Wold-Lyttkens (eds.) [33, Chapter 17].
5. Bergström, R. (1973). Studies of iterative methods for the estimation of interdependent systems, especially the FP and IIV methods. Doctoral Thesis, Univ. of Uppsala, Uppsala, Sweden, to be published.