Letter from Thomas Gold to Dr V S Troiskiy, Scientific Research Radiophysics Institute (Nauchno-issledovatel'skiy radiofizicheskiy institut--NIRFI), Gor'kiy, Arzamasskoye shosse, 17, USSR Asking for information on determining 'the internal temperature of the Moon and the internal heat flux'. Also wants information on their 'improvements in the techniques of measuring the radio emissions of the Moon'. 25 January 1968