Ormandy, Eugene, David Ewen and F. Warren O’Reilly. Letters. “Correspondence: with Eugene Ormandy, 1973,” 1973, Eugene Ormandy Papers, Kislak Center for Special Collection, Rare Books and Manuscripts, University of Pennsylvania, Philadelphia, Pennsylvania.
Stokowski, Leopold and Brooks Shepard. Lettters. “Correspondence with Leopold Stokowski, 1963-1964,” 1963-1964, Edwin A. Fleisher Music Collection, Irving S. Gilmore Music Library, Yale University, New Haven, Connecticut.
Correspondence from Charles and Harmony Twitchell Ives to Anton Rovinsky, 1928, 1951. General Manuscript Collection, Northwestern University Music Library, Evanston, Illinois.