"P. Jurgenson#1917 Russian Revolution" . . . "P. I. Jurgenson" . "Jurgenson" . "P. Jurgenson" . "Muzgiz" . . . . "Muzyka" . . "Boris P. Jurgenson" . "P. Jurgenson" . . . . . "1861" . "Peter Jurgenson" . . "Pyotr Jurgenson" . . "Muz\u00EFka" .