1. in Proceedings of First Marine Geodesy Symposiumnt Columbus, Ohio, 1966 (U.S. Government Printing Office, Washington;Bock R.;D. C.,1967
2. C. Bowin , C. Wing , T. Aldrich , J. Geophtys. Res. 74 , 3278 ( 1969 ).
3. C. G. Wing , ibid. 72 , 1249 ( 1967 ).
4. paper presented at Amer. Inst. Aeronaut. Astronaut. Astrodynamics Conf., Yale Univ;Anderson J. D.;New Haven,1963
5. W. N. Kaula NASA (Nat. Aeronaut. Space Admnin.) TN D-1847 (1963).