All transcripts and photocopies of correspondence to and from Edward, Helen and Myfanwy Thomas held in external collections across the UK, America and Canada
Myfanwy Thomas and the researcher R. George Thomas were chiefly responsible for bringing together copies and transcripts from these disparate locations in one place:
National Library of Wales, UK
National Library of Scotland, UK
British Library, London UK
Abbott Collection, University of Durham, UK
Battersea Public Library, UK
Eton School, UK
Bodleian Library, Oxford University, UK
Harry Ransome Centre, University of Austin, Texas, USA
Lockwood Memorial Library, University of Buffalo, USA
Berg Collection, New York Public Library, USA
Dartmouth College, New Hampshire, USA
Colbeck Collection, University of British Columbia, Canada