1. Andrews, D.F., P.J. Bickel, F.R. Hampel, P.J. Huber, W.H. Rogers, J.W. Tukey (1972): Robust estimates of Location. Princeton University Press, Princeton, New Jersey.
2. Arabelos, D., (1989): Gravity field approximation in the area of Greece with emphasis on local characteristics. Bull. Geod. Vol. 63. No.1, pp. 69–84.
3. Arabelos, D., P.Knudsen, C.C.Tscherning (1987): Covariance and bias treatment when combining gravimetry, altimeter and gradiometer data by collocation. XIX General Assembly IUGG, Vancouver.
4. Ayan, T.(1976): Astrogeodatische Geoidberechnung für das Gebiet der Turkei. Karlsruhe.
5. Ayhan, E. (1991): Local geoid determination by least squares collocation. Harita Dergisi, No. 106, pp. 91–110 (In Turkish).