Correspondence and progress reports regarding Luna 16 and 20, collected by Colin Pillinger Two progress reports created by the Organic Geochemistry Unit at the School of Chemistry, University of Bristol for Luna 16 and Luna 20 in 1973 , and correspondence with The Royal Society these. Correspondents: Professor Geoffrey Eglinton, University of Bristol T. Prigorowsky, The Royal Society Sir Kingsley Durham, The Royal Society January 1973-19 November 1975