Research papers of Peter Butter relating to his work on Edwin Muir and Willa Muir., 1913-circa1999., Acc.13634/13-55. Research papers and literary correspondence between Peter Butter and various correspondents relating to his work on Edwin and Willa Muir, William Blake, Francis Thompson and other writers., Acc.13634/1-77. National Library of Scotland Archives and Manuscripts Division. https://manuscripts.nls.uk/repositories/2/archival_objects/15263 Accessed May 03, 2024.