DUCKWORTH, Robert; HARVEY, John & POWELL, Julie. "Interview with George Crumb."
[http://www.thing.net/~roddys/trickyol/interview3.html]

HOLWIN, Mic. "Those Were The Days. Or Were They? Three Living Legends of Contemporary Music Compare Yesterday and Today (Interview with Georg Perle, George Crumb, and David Diamond)."
[http://www.americancomposers.org/millen1.htm]

WEST, Melissa. "A Deconstructive Reading of George Crumb's Black Angels." M.A. in Music Criticism, School of Art, Drama, and Music, McMaster University, September-December 1997.
[www.humanities.mcmaster.ca/~mus701/melissa/essay.htm]