Library of Congress. Copyright Office, U.S. Copyright Renewals, 1959 January - June
“ FIELD, JOHN. Nocturne in B-flat; piano. Biographical sketch, glossary, fingering, phrasing, pedaling, general information, instructive annotations on form and structure, interpretation, by Ernst C. Krohn. (Composition catalog, no. 665) © 18Sep31; AA78228. Art Publication Society (PWH) ”
