Library of Congress. Copyright Office, U.S. Copyright Renewals, 1954 July - December
“ SCHUMANN, ROBERT ALEXANDER. In der nacht (In the night) ; with biographical sketch, rev. ed. with fingering, pedaling and phrasing by Emil Sauer, general information, form and structure and interpretation by Arthur Edward Johnstone; pf. © 4Apr27; A992002. Art Publication Society (PWH) ”
