Lilja, Esa: Theory and Analysis of Classic Heavy Metal Harmony, s. 29–30. Helsingin yliopisto, humanistinen tiedekunta, taiteiden tutkimuksen laitos, 2009. Teoksen verkkoversio.
Chad Bowar Chad Bowar is a music journalist specializing in the heavy metal genre He publishes in national music publications, reviews major music festivals including Ozzfest, the Warped Tour: A Quick History Of Heavy MetalLiveAbout. Viitattu 1.7.2019. (englanniksi)