Boris Godunov opera in four acts with a prologue : libretto by the compopser, based on Pushkin's historical tragedy of the same name and Karamzin's "History of the Russian State" : the complete original texts of Mussorgky's "initial" (1869) and "definitive" (1872) versions with additional variants and fragments - Musorgskij, Modest Petrovič 1839-1881; Musorgskij, Modest Petrovič 1839-1881 (Oxford University Press, 1975)