Bulugh al-Maram
A’ishah (RAA) reported That Abu Bakr kissed the Prophet (ﷺ) after he had died.’ Related by Al-Bukhari.
وَعَنْهَا { أَنَّ أَبَا بَكْرٍ اَلصِّدِّيقَ - رضى الله عنه - قَبَّلَ اَلنَّبِيَّ - صلى الله عليه وسلم -بَعْدَ مَوْتِهِ } رَوَاهُ اَلْبُخَارِيُّ 1 .
Reference