Muhammad Alif Fitri Abdul Halim, <br/><br/>
Ensiklopedia empat khalifah :  Abu Bakar, Umar, Utsman, Ali / 
Alif Fitri ; editor bahasa Nurul Jannah, Maizatul Azlina ; editor syariah Amirul Arif, Alif Fitri, Hajar Hanisah 
 - xxiv, 303 pages :  color illustrations ;  28 cm. 
<br/><br/>Includes bibliographical references and index 
<br/><br/><label>ISBN: </label>9789673888214 
<br/><br/><label>Subjects--Personal Names: </label><br/>Muhammad Prophet --Companions
<br/><br/><label>Subjects--Topical Terms: </label><br/>Caliphs<br/>Caliphate