Wojska Polskiego powstałe po 1 września 1939 Further reading Seidner, Stanley S. Marshal Edward Śmigły-Rydz Rydz and the Defense of Poland, New York, 1978. Jan Wróblewski, Samodzielna Grupa Operacyjna Polesie 1939, MON, 1989, External links Final Order of General Keeberg to his soldiers Polesie Military units and formations established in 1939 Military units and formations of the Soviet invasion of Poland