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Qurʾān Bukhārī Muslim Nasāʾī Abū Dāwūd Tirmidhī Ibn Mājah Mālik Aḥmad Dārimī Ḥākim Ibn Ḥibbān Ṭabarānī Nasāʾī's Kubrá Bayhaqī al-Luʾluʾ wa-al-Marjān Ibn Rajab's Fifty Riyāḍ al-Ṣāliḥīn Aḥmad's Zuhd Suyūṭī
abudawud:4631 – Muḥammad b. Fāris > Qabīṣah > ʿAbbād al-Sammāk > Sufyān al-Thawrī > al-Khulafāʾ

The Caliphs are five: Abu Bakr, ‘Umar, ‘Uthman, ‘All and ‘Umar b. ‘Abd al-Aziz.  

أبو داود:٤٦٣١ – حَدَّثَنَا مُحَمَّدُ بْنُ فَارِسٍ حَدَّثَنَا قَبِيصَةُ حَدَّثَنَا عَبَّادٌ السَّمَّاكُ قَالَ

سَمِعْتُ سُفْيَانَ الثَّوْرِيَّ يَقُولُ الْخُلَفَاءُ خَمْسَةٌ أَبُو بَكْرٍ وَعُمَرُ وَعُثْمَانُ وَعَلِيٌّ وَعُمَرُ بْنُ عَبْدِ الْعَزِيزِ ؓ