Sahih al-Bukhari, Hadith 4489 ⓘ
Narrated Anas: None remains of those who prayed facing both Qiblas (that is, Jerusalem and Mecca) except myself.
حَدَّثَنَا عَلِيُّ بْنُ عَبْدِ اللَّهِ، حَدَّثَنَا مُعْتَمِرٌ، عَنْ أَبِيهِ، عَنْ أَنَسٍ ـ رضى الله عنه ـ قَالَ لَمْ يَبْقَ مِمَّنْ صَلَّى الْقِبْلَتَيْنِ غَيْرِي.
also referenced under: Book 65, Hadith 4489 (In-Book) & Volume 6, Book 60, Hadith 16 (USC-MSA)