أَخْبَرَنَا مُحَمَّدُ بْنُ عَبْدِ الأَعْلَى، قَالَ حَدَّثَنَا يَزِيدُ، - يَعْنِي ابْنَ زُرَيْعٍ - قَالَ حَدَّثَنَا سَعِيدٌ، قَالَ حَدَّثَنَا قَتَادَةُ، أَنَّ أَنَسَ بْنَ مَالِكٍ، حَدَّثَهُمْ أَنَّ نَبِيَّ اللَّهِ صلى الله عليه وسلم ضَحَّى بِكَبْشَيْنِ أَقْرَنَيْنِ أَمْلَحَيْنِ يَطَؤُ عَلَى صِفَاحِهِمَا وَيَذْبَحُهُمَا وَيُسَمِّي وَيُكَبِّرُ ‏.‏

It was narrated that Anas bin Malik told them that: the Prophet sacrificed two Amlah horned rams, putting his foot on their sides and slaughtering them pronouncing the name of Allah, and saying: Allahu Akbar."" (Sahih ) Translation Not Available

Book Ref: Sunan An Nisai Book 43 Hadith 4418
Web Ref:  Sunan An Nisai Vol 5 Book 43 Hadith 4423