International course for teacher training in environmental conservation and education, Rhyd-y-Creuau, The Drapers Field Centre, Betws-y-Coed Caernarvonshire, North Wales, United Kingdom, 2-12 August 1972 : final report 1972
Proceedings and papers : sixth Technical Meeting held at Edinburgh in June, 1956 simultaneously with the Union's 5th General Assembly 1957
