Sunan Abi Dawud · No. 999Chapter 2
" أَمَا يَكْفِي أَحَدَكُمْ - أَوْ أَحَدَهُمْ - أَنْ يَضَعَ يَدَهُ عَلَى فَخِذِهِ ثُمَّ يُسَلِّمُ عَلَى أَخِيهِ مَنْ عَنْ يَمِينِهِ وَمَنْ عَنْ شِمَالِهِ "
Is it not sufficient for one of you or for one of them that he puts his hand on his thigh, and then gives the salutation to his brother to his right and left sides.