↑ абRivadavia, Eduardo. Celtic Frost: Artist Biography. Allmusic. Процитовано 1 листопада 2014. On To Mega Therion, Warrior had begun experimenting with different musical styles (especially classical music and electronica), leading certain journalists to describe the band's direction as 'avant-garde' metal. Released in 1987, Into the Pandemonium would substantiate these claims and then some, introducing an unconventional collision of death metal brutality and symphonic overtones on its way to becoming one of the classic extreme metal albums of all time.
↑ абвDavies, Hywel; Dome, Malcolm; Goodman, Eleanor; Chantler, Chris; Gordon, Connie; Grady, Spencer; Rees, Adam; Selzer, Jonathan (17 листопада 2021). The 25 best symphonic metal albums. Metal Hammer. Future plc. Процитовано 2 січня 2022.