Abu al-Nasr,'Umar <br/><br/>
Khalifah Muhammad :  Abu Bakr al-Siddiq / 
'Umar Abu al-Nasr 
 - Beirut :  Matba'ah al-Wataniyah,  1934 
 - 166 p. ;  26 cm. 
<br/><br/><label>Subjects--Personal Names: </label><br/>Abu Bakr, Caliph, d.634