Smalley, Denis. “Review of 1974/02/02 Concert at Royal Northern College of Music, Manchester. Music Digest: The Music of Edgard Varèse. Saar Radio Symphony Orchestra Conducted by Hans Zender, Stephen Roberts (bass)”. Contact: A Journal for Contemporary Music (1971-1990), no. 8 (June 1, 1974). Accessed April 13, 2024. https://journals.gold.ac.uk/index.php/contactjournal/article/view/contactjournal08_p31-32.