Eisentraut, Jochen (2012). The Accessibility of Music: Participation, Reception, and Contact. Cambridge: Cambridge University Press. p. 111. ISBN978-1-107-02483-0. "progressive rock had an astounding success with the theoretically over-length (nearly 6 minute) single 'Bohemian Rhapsody' which bore many of the hallmarks of the 'prog' genre"
Prown, Pete; Newquist, H.P. (1997). Legends of Rock Guitar: The essential reference of rock's greatest guitarists. Milwaukee, Wisconsin: Hal Leonard Corporation. p. 106. ISBN978-0-793-54042-6. "'Bohemian Rhapsody' was akin to Led Zeppelin's 'Stairway to Heaven'. But while Zeppelin meshed folk influences with heavy metal, Queen opted for the light grandeur of the operetta as part of its hard rock."
