1. Heiskanen W A Moritz H Physical Geodesy San Francisco 1967
2. Downward continuation of airborne gravity data;Schwarz;OSU Report,1973
3. Downward continuation versus free-air reduction in airborne gravimetry;Keller;IAG Symposium,1992
4. Least-square collocation as a gravitational inverse problem;Moritz;USO Report,1978
5. Regularization wavelets and multiresolution;Freeden;Inverse Problem,1998