Hukumat'Umar ibn al-Khattab - Shibli Numani, Muhammad, 1857-1914 (Beirut : Dar al-'Arabiyah lil-Mawsu'at, 2004)
Keywords: 'Umar ibn al-Khattab, -- Caliph, -- d. 644; Islam and state; Political science -- Islamic Empire -- History