LDGSL/1107/A/1/6
Cambridge University, Jan-Mar 1969
Jan-Mar 1969
LDGSL/1107/A/1/8
Institute of Geophysics and Planetary Physics, University of California, 1969
Jul-Aug 1969
LDGSL/1107/A/1/11
General scientific correspondence, 1971
Jan-Jul 1971